Are you looking to enrapture and engage your readers?
Adjectives that start with O are an excellent way to enhance your article, essay, poem or story.
They also help to enlarge your vocabulary and make you an expert in the English language.
Let dive right in:
- Full List Chart (365 Words)
- Positive Adjectives That Start with O
- Negative Adjectives That Start with O
- Descriptive Adjectives Starting with O
- O Adjectives to Describe a Person
- Check All Definitions and Examples
- Infographic [Downloadable]
- Adjectives Starting with Other Letters
Full List of Adjectives That Start with O
Let’s begin with a full list of adjectives that start with O. Please be patient because this is a long list.
| Oafish | Only | Outermost |
| Oaken | Onomastic | Outflowing |
| Oaten | Onshore | Outgoing |
| Obdurate | Onside | Outlandish |
| Obedient | Onstage | Outlaw |
| Obese | Ontogenetic | Outlawed |
| Objectionable | Ontological | Outlying |
| Objective | Onymous | Outmoded |
| Oblanceolate | Oozy | Outmost |
| Oblate | Opalescent | Outraged |
| Obligate | Opaline | Outrageous |
| Obligated | Opaque | Outre |
| Obligational | Open | Outrigged |
| Obligatory | Opencast | Outright |
| Obliging | Opencut | Outside |
| Oblique | Openhanded | Outsized |
| Obliterable | Openhearted | Outspoken |
| Obliterate | Openmouthed | Outspread |
| Obliterated | Operable | Outstanding |
| Oblivious | Operant | Outstretched |
| Oblong | Operatic | Outward |
| Obnoxious | Operating | Oval |
| Obovate | Operational | Ovarian |
| Obscene | Operative | Ovate |
| Obscure | Operculate | Over |
| Obsequious | Operculated | Overabundant |
| Observable | Operose | Overactive |
| Observant | Ophthalmic | Overaged |
| Observational | Opinionated | Overaggressive |
| Observing | Opinionative | Overall |
| Obsessional | Opponent | Overambitious |
| Obsessive | Opportune | Overanxious |
| Obsolescent | Opportunistic | Overarm |
| Obsolete | Opposed | Overbearing |
| Obstetric | Opposing | Overblown |
| Obstetrical | Opposite | Overbold |
| Obstinate | Oppositive | Overburdened |
| Obstreperous | Oppressive | Overbusy |
| Obstructed | Opprobrious | Overcareful |
| Obstructive | Optative | Overcast |
| Obtainable | Optic | Overcautious |
| Obtrusive | Optical | Overconfident |
| Obtuse | Optimal | Overcooked |
| Obvious | Optimistic | Overcredulous |
| Occasional | Optimum | Overcritical |
| Occidental | Optional | Overcrowded |
| Occipital | Opulent | Overcurious |
| Occluded | Oracular | Overdelicate |
| Occlusive | Oral | Overdressed |
| Occult | Orange | Overdue |
| Occupational | Orangish | Overemotional |
| Occupied | Oratorical | Overenthusiastic |
| Occurrent | Orbicular | Overexcited |
| Oceangoing | Orbiculate | Overfamiliar |
| Oceanic | Orbital | Overfed |
| Ocellated | Orbitual | Overfond |
| Ocher | Orchestral | Overfull |
| Ochre | Ordained | Overgenerous |
| Octagonal | Ordered | Overgreedy |
| Octal | Orderly | Overgrown |
| Octangular | Ordinal | Overhand |
| Octogenarian | Ordinary | Overhanded |
| Octosyllabic | Organic | Overhasty |
| Octuple | Organicistic | Overhead |
| Ocular | Organisational | Overheated |
| Odd | Organised | Overindulgent |
| Oddish | Organismal | Overjealous |
| Odiferous | Organismic | Overjoyed |
| Odious | Organizational | Overladen |
| Odoriferous | Organized | Overland |
| Odorless | Orgiastic | Overlarge |
| Odorous | Oriental | Overlying |
| Odourless | Orientated | Overmodest |
| Oecumenic | Oriented | Overmuch |
| Oecumenical | Original | Overnice |
| Offbeat | Originative | Overnight |
| Offenseless | Ornamental | Overoptimistic |
| Offensive | Ornate | Overpowering |
| Offhand | Ornery | Overpriced |
| Offhanded | Ornithological | Overprotective |
| Official | Oropharyngeal | Overproud |
| Officious | Orotund | Overqualified |
| Offish | Orphaned | Overrated |
| Offshore | Orphic | Overrefined |
| Offside | Orthodox | Overripe |
| Offstage | Orthogonal | Oversea |
| Ohmic | Orthomolecular | Overseas |
| Oily | Orthopaedic | Oversensitive |
| Old | Orthopedic | Overserious |
| Olden | Orthopedical | Oversewn |
| Oldish | Orthoptic | Oversexed |
| Oldline | Orthostatic | Overshot |
| Oleaceous | Orthotropous | Oversize |
| Oleaginous | Orwellian | Oversized |
| Oleophilic | Oscine | Oversolicitous |
| Oleophobic | Oscitant | Overstrung |
| Olfactive | Osseous | Overstuffed |
| Olfactory | Ossicular | Oversubscribed |
| Oligarchic | Ossiculate | Oversuspicious |
| Olive | Ossiferous | Overt |
| Olivelike | Ossified | Overvaliant |
| Olympian | Osteal | Overweening |
| Olympic | Ostensible | Overweight |
| Omani | Ostensive | Overwhelmed |
| Ominous | Ostentatious | Overwhelming |
| Omissible | Other | Overworked |
| Omissive | Otherwise | Overwrought |
| Omnibus | Otherworldly | Overzealous |
| Omnidirectional | Otic | Oviform |
| Omnifarious | Otiose | Ovine |
| Omnipotent | Ototoxic | Oviparous |
| Omnipresent | Ottoman | Ovoid |
| Omniscient | Outback | Ovoviviparous |
| Omnivorous | Outboard | Owing |
| Oncologic | Outbound | Owlish |
| Oncoming | Outbred | Own |
| One | Outcast | Owned |
| Oneiric | Outcaste | Ownerless |
| Onerous | Outclassed | Oxidative |
| Onetime | Outdated | Oxidised |
| Ongoing | Outdoor | Oxidizable |
| Online | Outer |
Positive Adjectives That Start with O
I believe “optimistic” must be one of the positive adjectives that start with O that come to your mind. But let’s check more.
| Obedient | Online | Oracular |
| Objective | Only | Orchestral |
| Obligated | Opalescent | Ordained |
| Obliging | Opaline | Ordered |
| Observable | Open | Orderly |
| Observant | Open-ended | Organic |
| Observational | Openhearted | Organized |
| Obtainable | Open-minded | Orientated |
| Obvious | Operable | Orientating |
| Occurrent | Operant | Oriented |
| Official | Operatic | Original |
| OK | Operating | Originative |
| Olympian | Operational | Ornamental |
| Olympic | Operative | Ornate |
| Omnibus | Opportune | Orotund |
| Omnidirectional | Opportunist | Orthodox |
| Omnipotent | Opportunistic | Overabundant |
| Omnipresent | Optimal | Overall |
| Omniscient | Optimistic | Overjoyed |
| One | Optimum | Overt |
| Onetime | Optional | Opulent |
| Ongoing |
Negative Adjectives That Start with O
Now it comes to the category of negative adjectives starting with O. Check and see if you can add more.
| Oafish | Obtuse | Opposite |
| Obdurate | Occluded | Oppressive |
| Obese | Occult | Outcast |
| Objectionable | Occupied | Outclassed |
| Obligated | Odd | Outdated |
| Obligational | Odious | Outlaw |
| Obligatory | Off | Outlawed |
| Obliterable | Offensive | Outmoded |
| Obsessive | Oily | Outraged |
| Obsolete | Old | Outrageous |
| Obstinate | Omissible | Overactive |
| Obstreperous | Omissive | Overaged |
| Obstructed | Oozy | Overbearing |
| Obstructive | Opponent | Overburdened |
| Obtrusive | Opportunistic | Owing |
Descriptive Adjectives That Start with O
Following descriptive words that start with O can be used to describe certain emotions, people, and places.
| Oaken | Offhand | Ordinary |
| Obligated | Official | Oriental |
| Obliging | Offshore | Oriented |
| Oblique | Offstage | Ornate |
| Obliterable | Old | Orthopedic |
| Obliterated | Olden | Orwellian |
| Oblivious | Olfactory | Ostensive |
| Oblong | Olive | Other |
| Obscure | Omissible | Out |
| Observable | Oncological | Outbound |
| Observant | Oncoming | Outdoor |
| Obstinate | One | Outgoing |
| Obstructed | Ongoing | Outlandish |
| Obstructive | Only | Ovation |
| Obtainable | Onshore | Overage |
| Obtrusive | Opaque | Overall |
| Obtuse | Open | Overcast |
| Obvious | Operant | Overcoming |
| Occasional | Operating | Overhead |
| Occipital | Opinionated | Overland |
| Occluded | Opponent | Overly |
| Occupational | Opportunist | Overnight |
| Occupied | Opposite | Overshot |
| Oceanic | Optic | Overstuffed |
| Ochre | Optional | Overt |
| Octangular | Oral | Overweight |
| Octogenarian | Orange | Ovid |
| Odious | Orbital | Own |
| Odorless | Orchestral | Owned |
| Off | Ordained | Ownerless |
| Offbeat | Ordeal | Oxidized |
| Offensive | Ordered | Oxlike |
Adjectives That Start with O to Describe a Person
Feeling stuck when describing people? This is when you need to check following adjectives starting with O.
| Objectionable | Outdoorsy | Overdeveloped |
| Obscene | Outgoing | Overdosed |
| Odd | Outlandish | Overdressed |
| Odious | Outlaw | Overeducated |
| Offensive | Outmoded | Overexerted |
| OK | Outrageous | Overexerting |
| Okay | Outright | Overexposed |
| Old | Outspoken | Overextended |
| Oldish | Outspread | Overfatigued |
| Open | Outstanding | Overfed |
| Openhanded | Overbooked | Overfulfilled |
| Orderly | Overburdened | Overinformed |
| Ordinary | Overcharged | Oversteered |
| Outcast | Overcoached | Overweight |
| Outclassed | Overcommitted | Overwhelming |
| Outdated | Overcounted | Overdeveloped |
Adjectives That Start with O – Definitions and Examples
Since you’ve gone through all the adjectives that begin with O, now it’s time to review their definitions and examples.
Oafish: especially of a man stupid, unpleasant or rough; agile; awkward.
– Don’t put up with oafish behaviour.
Oaken: made of oak; woody; wooden.
– The press box first consisted of strongly bound oaken planks, but later on cast-iron boxes were introduced.
Oaten: of, pertaining to, or made of oats; Avena; genus Avena.
– Janet looked, and by the light of Will o’ Wisp she could just catch sight of their little oaten pipes.
Obdurate: refusing to change your mind or your actions in any way; stubborn; pig-headed.
– An obdurate attitude.
Obedient: doing what you are told to do; willing to obey; compliant; acquiescent.
– He was always obedient to his father’s wishes.
Obese: very fat, in a way that is not healthy; overweight; plump.
– Obese patients are given dietary advice.
Objectionable: unpleasant or offensive; disagreeable; distasteful.
– I myself didn’t find his behaviour objectionable.
Oblanceolate: having a rounded apex and a tapering base; unsubdivided; simple.
– Leaves on the youngest plants are simple and oblanceolate, but large lobed intermediate leaves soon appear.
Oblate: flattened or depressed at the poles; empty; horizontal.
– He showed that a thin shell full of water spins stably when slightly oblate but is violently unstable when slightly prolate.
Obligate: morally or legally bound; obliged; constraine; necessary; essential.
– Cats are obligate carnivores, meaning that they must eat meat in order to survive.
Obligated: obligated (to do something) having a moral or legal duty to do something; obliged; compel.
– He felt obligated to help.
Obligational: relating or constituting or qualified to create a legal or financial obligation; accountability; charge.
– Obligational authority.
Obligatory: that you must do because of the law, rules; compulsory; mandatory.
– The college authorities have now made these classes obligatory.
Obliging: very willing to help; accommodating; helpful.
– They were very obliging and offered to wait for us.
Oblique: not expressed or done in a direct way; indirect; inexplicit.
– An oblique reference.
Obliterable: able to be obliterated completely; removable; eradicable; able to be eradicated or rooted out.
– Not obliterable facts.
Obliterated: destroyed; broken beyond repair; destroy; wipe out.
– The building was completely obliterated by the bomb.
Oblivious: not aware of something; unconscious; heedless.
– You eventually become oblivious to the noise.
Oblong: used to describe any shape that is longer than it is wide; oval; ovoid.
– An oblong melon.
Obnoxious: extremely unpleasant, especially in a way that offends people; offensive; disagreeable.
– The movie is loud and obnoxious.
Obovate: shaped like the longitudinal section of an egg with the narrower end at the base; inversely ovate; egg-shaped; ellipsoidal.
– The leaf in its contour is somewhat obovate.
Obscene: extremely large in size or amount in a way that most people find unacceptable and offensive; outrageous; indecent; salacious.
– He earns an obscene amount of money.
Obscure: not well known; unknown; uncertain.
– We went to see one of Shakespeare’s more obscure plays.
Obsequious: trying too hard to please somebody, especially somebody who is important; servile; ingratiating.
– The waiters came hurrying forward with obsequious smiles on their faces.
Observable: that can be seen or noticed; noticeable; visible.
– Similar trends are observable in mainland Europe.
Observant: good at noticing things around you; sharp-eyed; eagle-eyed.
– Observant walkers may see red deer along this stretch of the road.
Observational: connected with or based on the activity of watching somebody/something carefully for a period of time, especially to learn something; experimental; factual.
– The course helps drivers to improve their observational skills.
Observing: quick to notice; showing quick and keen perception; observant perceptive; having the ability to perceive or understand; keen in discernment.
– She suspected he was observing what happened.
Obsessional: thinking too much about one particular person or thing, in a way that is not reasonable or normal; obsessive; compulsive.
– She is obsessional about cleanliness.
Obsessive: thinking too much about one particular person or thing, in a way that is not reasonable or normal; consuming; compulsive.
– He’s becoming more and more obsessive about punctuality.
Obsolescent: becoming old-fashioned and no longer useful; going out of fashion; on the decline.
– Obsolescent equipment.
Obsolete: no longer used because something new has been invented; out of date; outdated; outmoded.
– With technological changes many traditional skills have become obsolete.
Obstetric: connected with the branch of medicine that deals with the birth of children; fetology; perinatology.
– Obstetric medicine.
Obstetrical: of or relating to childbirth or obstetrics; fetology; perinatology.
– For the first time in history an obstetrical maneuver is named after a midwife.
Obstinate: refusing to change your opinions, way of behaving, etc. when other people try to persuade you to; showing this; stubborn; obdurate.
– Their position remains one of obstinate denial, even in face of the new evidence.
Obstreperous: noisy and difficult to control; unmanageable; disorderly.
– The teenagers became obstreperous when their school team lost the football game.
Obstructed: shut off to passage or view or hindered from action; block; clog.
– A partially obstructed passageway.
Obstructive: trying to prevent somebody/something from making progress; unhelpful; uncooperative.
– Of course she can do it. She’s just being deliberately obstructive.
Obtainable: that can be obtained; available; in circulation.
– Full details are obtainable from any post office.
Obtrusive: easy to notice in an unpleasant way; conspicuous; prominent.
– The sofa would be less obtrusive in a paler colour.
Obtuse: slow or unwilling to understand something; stupid; dull.
– He was either completely ignorant or being willfully obtuse.
Obvious: easy to see or understand; clear; plain.
– I know you don’t like her but try not to make it so obvious.
Occasional: happening or done sometimes but not often; infrequent; intermittent.
– He works for us on an occasional basis.
Occidental: from or connected with the western part of the world, especially Europe and America; west; western.
– While tutoring Chinese children online, I teach English to the students as well as some of the occidental customs of America.
Occipital: of or relating to the back of the head or skull; pate; cranium.
– He had a face like a skull with the skin drawn tightly over occipital and malar ridges.
Occluded: shut off to passage or view or hindered from action; closed off; obstructed.
– An occluded artery.
Occlusive: tending to occlude; a consonant produced by stopping the flow of air at some point and suddenly releasing it; barricade; barrier.
– The coronary arteries showed severe generalized occlusive atheroma affecting all the main branches.
Occult: connected with magic powers and things that cannot be explained by reason or science; supernatural; paranormal.
– Occult practices.
Occupational: connected with a person’s job or profession; professional; vocational.
– Occupational health.
Occupied: being used by somebody; engage; busy; employ.
– Only half of the rooms are occupied at the moment.
Occurrent: occurring at a particular time or place; current; incidental.
– Complaints seemed to be occurrent at every Tuesdays.
Oceangoing: made for crossing the sea or ocean, not for journeys along the coast or up rivers; aquatic; coastal.
– She was the workhorse of the oceangoing vessels of her time.
Oceanic: living in or connected with the ocean; aquatic; pelagic.
– Oceanic fish.
Ocellated: Of, pertaining to, resembling or having an ocellus; simple eye; stemma.
– The ocellated turkey has an eye-shaped spot on its tail feathers.
Ochre: of a moderate orange-yellow color; ocher; chromatic.
– She paints herself with red ochre, some of which spills onto the clouds, creating the sunrise.
Octagonal: having eight sides; octave; octet.
– An octagonal coin.
Octal: of or pertaining to a number system having 8 as its base; base.
– An octal digit.
Octangular: having eight angles; octave; octet.
– The dome is octagonal.
Octosyllabic: consisting of eight syllables; octosyllable; syllabic.
– He soon takes up the simple octosyllabic couplet, treated, however, with great freedom.
Octuple: eightfold; eight times as great; having eight effective units or elements.
– An octuple machine.
Ocular: connected with the eyes; optic; visual.
– Ocular muscles.
Odd: strange or unusual; peculiar; weird.
– There’s something odd about that man.
Oddish: somewhat strange; strange; unusual; slightly odd or even a bit weird.
– Some time ago a grave, oddish kind of a man boarded at a farmer’s in this parish.
Odiferous: having a natural fragrance; odorous; ill-smelling; malodorous.
– Lead is easily purified away from the odiferous sulfur.
Odious: extremely unpleasant; horrible; abhorrent.
– What an odious man!
Odoriferous: yielding an odor; odorous; morally offensive.
– Ammonia is a highly odoriferous and exceptionally volatile substance.
Odorless: without a smell; unscented; unperfumed.
– An odourless liquid.
Odorous: having a smell; smelly; stinking.
– Odorous gases.
Odourless: without a smell; unscented; unperfumed.
– An odourless liquid.
Oecumenical: of worldwide scope or applicability; cosmopolitan; ecumenical; general.
– It remained an oecumenical school until its closure by the Britons.
Offbeat: different from what most people expect; unconventional; unorthodox.
– Offbeat humor.
Offenseless: without offense; incapable of offense or attack; inoffensive; unoffending.
– They are followed on the schedule by the offenseless Giants.
Offensive: rude in a way that causes somebody to feel upset or annoyed because it shows a lack of respect; insulting; rude.
– Offensive remarks.
Offhand: not showing much interest in somebody/something in a way that is rude or upsets somebody; indifferent; casual.
– He was very offhand with me.
Offhanded: a remark or comment that is made without previous thought or preparation; extemporaneous; extemporary.
– She stared up at him in amazement as she absorbed his offhanded invitation.
Official: agreed to, said, done, etc. by somebody who is in a position of authority; ceremonial; formal.
– The news is not yet official.
Officious: too ready to tell people what to do or to use the power you have to give orders; self-important; intrusive.
– A nasty officious little man.
Offish: aloof; unapproachable; standoffish.
– I want a go back to the offish and clean out that bunch of stiffs.
Offshore: happening or existing in the sea, not far from the land; coastal; nearshore.
– Offshore drilling.
Offside: in some sports, for example football (soccer) and ice hockey, a player is offside if they are in a position, usually ahead of the ball, that is not allowed; erroneous; inaccurate.
– He was offside when he scored.
Offstage: not on the stage in a theatre; not where the audience can see; private; secret.
– Offstage sound effects.
Ohmic: of or relating to a circuit element, the electrical resistance of which obeys Ohm’s law; active; dynamic; energetic.
– As the core temperature rises, so does its resistivity and therefore the ohmic heating rate escalates.
Oily: containing or covered with oil; greasy; fatty.
– He had rather oily hands.
Old: having lived for a long time; no longer young; elderly; mature.
– The old man lay propped up on cushions.
Olden: a long time ago in the past; aboriginal; age-old.
– What was life like in the olden days, Gran?
Oldish: fairly old; aged; ancient.
– The typewriter, an oldish electric model, stood on the dining-table.
Oldline: following or supporting conservative or traditional ideas, beliefs, customs; long established; traditional; old-line society.
– His more oldline colleagues expressed their concern with the changes.
Oleaginous: covered in or containing a lot of oil or grease; greasy; oily.
– Large numbers of oleaginous plants are cultivated, such as sunflower.
Oleophilic: having or relating to strong affinity for oils; hydrophilic; lipophilic; lyophilic.
– All coatings are hydrophobic and oleophilic.
Oleophobic: having or relating to a lack of strong affinity for oils; hydrophilic; hydrophobic sense; lyophobic.
– The new oleophobic screen is brighter and displays warmer.
Olfactive: Of or pertaining to the sense of smell; olfactory; aromatic; balmy.
– The olfactive descriptions of floral scent from each species was evaluated for a professional perfumer.
Olfactory: connected with the sense of smell; flavorsome; flowery.
– Olfactory cells.
Olive: grey-green in colour; beryl; chartreuse.
– A dark olive green carpet.
Olivelike: resembling an olive; olivelike rounded; curving and somewhat round in shape rather than jagged.
– These steamers carry on an exchange of European goods for ivory, palm oil, and butter from the olivelike seeds of the butter tree.
Olympian: relating to the ancient or modern Olympic games; angelic; divine.
– Olympian gymnasts.
Olympic: connected with the Olympic Games; Olympic Games; athletics.
– The British Olympic team.
Omani: a person from Oman; Arabian Peninsula; Gulf States.
– This is the end of Omani influence, and there is a small fort as a protection against the Mahri.
Ominous: suggesting that something bad is going to happen in the future; foreboding; threatening.
– There were ominous dark clouds gathering overhead.
Omissible: capable of being or allowed to be omitted; incident; incidental.
– The genitive bit is often optionally omissible with nouns.
Omissive: leaving out; failing or neglecting to do; omitting.
– Omissive contract.
Omnibus: including many things or different types of thing; comprehensive; panoramic.
– An omnibus law.
Omnidirectional: receiving or sending signals in all directions; position; spatial relation.
– An omnidirectional microphone.
Omnifarious: Of many or all forms, varieties, or kinds; exceedingly varied; disparate; divergent.
– The political panel was omnifarious in order to spark debates.
Omnipotent: having total power; able to do anything; all-powerful; almighty.
– An omnipotent God.
Omnipresent: present everywhere; ubiquitous; general.
– These days the media are omnipresent.
Omniscient: knowing everything; all-knowing; all-wise.
– The novel has an omniscient narrator.
Omnivorous: eating all types of food, especially both plants and meat; having wide interests in a particular area or activity; undiscriminating; indiscriminate.
– She has always been an omnivorous reader.
Oncoming: coming towards you; approaching; advancing.
– Always walk facing the oncoming traffic.
Oneiric: of, relating to, or suggestive of dreams; dreamy; dreamish.
– The film thrills with its indelible, oneiric imagery.
Onerous: needing great effort; causing trouble or worry; taxing; burdensome.
– An onerous duty.
Onetime: former; former; ex.
– Her onetime best friend, Anna.
Ongoing: continuing to exist or develop; in progress; under way.
– The police investigation is ongoing.
Online: available on or done using the internet or other computer network; networked; wired.
– Online shopping is both cheap and convenient.
Only: used to say that no other or others of the same group exist or are there; sole; single.
– She’s their only daughter.
Onshore: on or towards land; ashore; inshore.
– An onshore oil field.
Onside: to get/keep somebody’s support; approve; back.
– The party needs to keep the major national newspapers onside if it’s going to win the next election.
Onstage: on the stage in a theatre; in front of an audience; perform; play.
– Onstage fights.
Ontogenetic: of or relating to the origin and development of individual organisms; advancement; evolution.
– What they contemplated was an ontogenetic change.
Ontological: connected with the branch of philosophy that deals with the nature of existence; philosophical; metaphysical.
– A system of ontological categories.
Onymous: having a name; named; binomial; binominal.
– Articles in magazines are usually onymous.
Oozy: full of very soft mud; clammy; glutinous.
– An oozy river bed.
Opalescent: changing colour like an opal; multicolored; prismatic.
– An opalescent sky.
Opaline: resembling opal in its iridescence; having a milky white iridescence; iridescent; nacreous.
– She thought she saw her son’s face leaning over her, blocking out the opaline glare of the sun.
Opaque: difficult to understand; not clear; impenetrable.
– The jargon in his talk was opaque to me.
Open: allowing things or people to go through; not closed or blocked; unlocked; unbolted.
– A wasp flew in the open window.
Opencast: in opencast mines coal is taken directly out of the ground near the surface, without digging tunnels; open-pit; open-source.
– Opencast mines.
Openhanded: generous and giving willingly; charitable; benevolent.
– An openhanded host.
Openhearted: kind and friendly; unreserved; candid; frank.
– Openhearted advice.
Openmouthed: with your mouth open because you are surprised or shocked; astounded; amazed.
– The kids stared openmouthed at the screen.
Operable: that functions; that can be used; functional; operational.
– Less than half the rail network was operable.
Operant: functioning or tending to produce effects; effective; efficacious.
– These are classical and operant conditioning.
Operatic: connected with opera; rhapsodic; rhythmic.
– Operatic arias/composers.
Operating: used or engaged in performing operations; operational; running.
– An operating surgeon.
Operational: ready or available to be used; connected with the way in which a business, machine, system, etc. works; functioning; operative.
– The new airport is now fully operational.
Operative: a worker, especially one who works with their hands; effective; functioning.
– A factory operative.
Operose: tedious, wearisome; arduous; diligent; hard.
– Dana wasn’t used to doing operose work outdoors.
Ophthalmic: connected with the eye; sight; visual.
– Ophthalmic surgery.
Opinionated: having very strong opinions that you are not willing to change; pontifical; doctrinaire.
– I’ve never met anyone so arrogant and opinionated.
Opponent: a person that you are playing or fighting against in a game, competition, argument; adversary; rival.
– A political opponent.
Opportune: suitable for doing a particular thing, so that it is likely to be successful; auspicious; propitious.
– The offer could not have come at a more opportune moment.
Opportunistic: making use of an opportunity, especially to get an advantage for yourself; not done in a planned way; eager; enthusiastic.
– They must be allowed to pursue opportunistic deals.
Opposed: disagreeing strongly with something and trying to stop it; in opposition; averse.
– He was strongly opposed to modernism in art.
Opposing: playing, fighting, and working, etc. against each other; opposite; combatant.
– It is time for opposing factions to unite and work towards a common goal.
Opposite: on the other side of a particular area from somebody/something and usually facing them; conflicting; incompatible.
– Answers are given on the opposite page.
Oppressive: treating people in a cruel and unfair way and not giving them the same freedom, rights, etc. as other people; harsh; cruel.
– Oppressive laws.
Opprobrious: expressing severe criticism of somebody; abusive; vituperative.
– An opprobrious remark.
Optic: connected with the eye or the sense of sight; ocular; optical.
– The optic nerve.
Optical: connected with the sense of sight or the relationship between light and sight; visual; ocular.
– Optical effects.
Optimal: the best possible; producing the best possible results; excellent.
– The optimal economic position for households is represented by point B on the chart.
Optimistic: expecting good things to happen or something to be successful; showing this feeling; positive.
– We are now taking a more optimistic view.
Optimum: the best possible; producing the best possible results; ideal; perfect.
– The optimum use of resources.
Optional: that you can choose to do or have if you want to; non-mandatory; open.
– Certain courses are compulsory; others are optional.
Opulent: made or decorated using expensive materials; luxurious; lavish; deluxe.
– Opulent fabrics/surroundings.
Oracular: of or like an oracle; with a hidden meaning; predictive.
– All he did was to make an oracular statement.
Oral: spoken rather than written; spoken; verbal; unwritten.
– A test of both oral and written French.
Orange: between red and yellow in colour; peach; apricot.
– There was a warm orange glow in the sky.
Orangish: of the color between red and yellow; similar to the color of a ripe orange; apricot.
– Did you see the orangish flower petals in the salad? They are flower petals and I ate them.
Oratorical: connected with the art of public speaking; rhetorical; grandiloquent.
– Oratorical skills.
Orbicular: having the shape of a flat ring or disc; oblique; round.
– The household ruin was thus full and orbicular.
Orbiculate: circular or nearly circular; orbicular; simple.
– The species has an orbiculate carapace and legs covered in barbed.
Orbital: connected with the orbit of a planet or object in space; gamut; range.
– The newly discovered world followed an orbital path unlike that of any other planet.
Orchestral: connected with an orchestra; concert; instrumental.
– Orchestral music.
Ordered: carefully arranged or organized; orderly; arranged; organized.
– An ordered existence.
Orderly: arranged or organized in a neat, careful and logical way; tidy; trim.
– A calm and orderly life.
Ordinal: referring to or connected with the position of something in a series; figure; statistic.
– The ordinal numbers.
Ordinary: not unusual or different in any way; usual; normal.
– An ordinary sort of day.
Organic: produced by or from living things; biological; natural.
– Improve the soil by adding organic matter.
Organisational: connected with the way in which the different parts of something are arranged; connected with an organization; structural; bureaucratic.
– Organisational changes within the party.
Organised: planned and controlled on a large scale and involving many people; arranged; sorted.
– The parade was very well organised.
Organismal: of or relating to or belonging to an organism; creature; structure.
– Organismal ageing is characterized by functional decline of tissues and organs with age and this is most obvious in situations of injury or stress.
Organizational: connected with the way in which the different parts of something are arranged; connected with an organization; structural; managerial.
– Organizational changes within the party.
Organized: involving large numbers of people who work together to do something in a way that has been carefully planned; arrange; sort.
– An organized system of childcare.
Orgiastic: typical of an orgy; debauched; wild.
– Orgiastic delight.
Oriental: connected with or typical of the eastern part of the world, especially China and Japan, and the people who live there; eastern; Chinese.
– Oriental languages.
Orientated: concerned with or directed towards someone or something; oriented adjusted; familiarized.
– The burial of a man was found within the circle, and the cove may have been orientated toward the major northern moonrise.
Original: existing at the beginning of a particular period, process or activity; authentic; genuine.
– The room still has many of its original features.
Originative: containing seeds of later development; germinal; seminal.
– That these ideas are to be traced, ultimately, to the originative or intuitive faculty, there can be little doubt.
Ornamental: used as decoration rather than for a practical purpose; decorative; fancy.
– The chimney pots are purely ornamental.
Ornate: covered with a lot of decoration, especially when this involves very small or complicated designs; elaborate; decorated.
– This style is a little too ornate for my taste.
Ornery/: easily annoyed and difficult to deal with; grouchy; grumpy.
– He had been in an ornery mood all day, arguing with everyone who got in his way.
Ornithological: connected with the scientific study of birds; ornithology; bird-watching.
– Ornithological research.
Orotund: using full and impressive sounds and language; sonorous; strong.
– The millionaire’s orotund manner made him come across as arrogant.
Orphic: of or pertaining to Orphism, its doctrines and rituals; mystic; darkling.
– On the whole, however, our Orphic authorities can never be quoted with much satisfaction.
Orthodox: generally accepted or approved of; following generally accepted beliefs; traditional; conservative.
– He is very orthodox in his views.
Orthogonal: relating to, consisting of, or involving right angles; perpendicular; rectangular.
– The rings have 120 bridge, and are almost orthogonal to each other.
Orthopaedic: connected with the branch of medicine that deals with injuries and diseases of the bones or muscles; physiatrist; physician.
– He wanted to specialize in sports medicine, and be an orthopaedic surgeon.
Orthopedic: connected with the branch of medicine that deals with injuries and diseases of the bones or muscles; neurologist; physiatrist.
– An orthopedic surgeon.
Orthoptic: relating to normal binocular vision; treatment; intervention.
– Orthoptic exercises.
Orthostatic: of or caused by an upright position; vertical; erect.
– Orthostatic hypotension.
Orwellian: used to describe a political system in which a government tries to have complete control over people’s behaviour and thoughts; author; writer.
– We don’t want to see a 1984 Orwellian type situation where neighbours are reporting on neighbors.
Oscitant: showing lack of attention or boredom; drowsy; yawning; inattentive.
– Sleepy and oscitant, the drowsy delivery man fought back a yawn as he tried to stay awake.
Osseous: made of or turned into bone; skeletal; anatomical.
– Osseous tissue can bind more calcium salt without resorption.
Ossiferous: containing bones, especially fossil bones; ossified; connective tissue.
– Ossiferous caves and rock beds.
Ossified: having turned into bone or bony tissue; harden; solidify.
– Ossified cartilage.
Osteal: of, relating to, or resembling bone; affecting or involving bone or the skeleton; bony; osseous.
– There was not any bad result, either in osteal or in functional outcome.
Ostensible: seeming or stated to be real or true, when this is perhaps not the case; apparent; purported.
– The ostensible reason for his absence was illness.
Ostensive: represented or appearing as such; pretended; imitative; not genuine.
– Ostensible counterfeit.
Ostentatious: showing your wealth or status in a way that is intended to impress people; showy; pretentious.
– Ostentatious gold jewellery.
Other: used to refer to people or things that are additional or different to people or things that have been mentioned or are known about; added; supplementary.
– Mr. Harris and Mrs. Bate and three other teachers were there.
Otherwise: used to state what the result would be if something did not happen or if the situation were different; apart from that; or else.
– My parents lent me the money. Otherwise, I couldn’t have afforded the trip.
Otherworldly: connected with spiritual thoughts and ideas rather than with ordinary life; ethereal; heavenly.
– There was an otherworldly quality to her performance that night.
Otic: of, relating to, or located in the region of the ear; auditory; auricular.
– Another opening was made in the otic capsule near the helicotrema.
Otiose: having no useful purpose; unnecessary; empty; hollow.
– An otiose round of meetings.
Ototoxic: having a harmful effect on the organs or nerves concerned with hearing and balance; toxic.
– Some drugs are ototoxic.
Outboard: on, towards or near the outside of a ship or an aircraft; inboard; powerboat.
– Outboard wing panels.
Outbound: travelling from a place rather than arriving in it; departing; retiring.
– Outbound flights.
Outbred: bred of parents; not closely related; having parents of different classes or tribes.
– We developed a standardized protocol to create, replicate and maintain isofemale lines and outbred populations.
Outcast: not accepted by society or by a particular group; fugitive; untouchable.
– He had been made to feel socially outcast.
Outcaste: rejected or discarded; fugitive; untouchable.
– But the Chinese visitors were in company with the foreigners, and all foreigners were outcaste in this eastern plain.
Outdated: no longer useful because of being old-fashioned; out of date; unfashionable.
– These figures are now outdated.
Outdoor: used, happening or located outside rather than in a building; outside; open-air.
– They sell camping equipment, hiking gear and outdoor clothing.
Outer: on the outside of something; external; outside; outermost.
– While the chassis is made of steel, the outer shell is plastic.
Outermost: furthest from the inside or center; beyond; distant.
– He fired and hit the outermost ring of the target.
Outflowing: that is flowing outward; effluent outgoing; leaving a place or a position.
– Outflowing water.
Outgoing: liking to meet other people, enjoying their company and being friendly towards them; sociable; extrovert.
– She was always cheerful and outgoing.
Outlandish: strange or extremely unusual; bizarre; weird.
– As the show progressed, it got ever more outlandish.
Outlying: far away from the cities of a country or from the main part of a place; distant; remote.
– Outlying areas.
Outmoded: no longer fashionable or useful; old-fashioned; outdated.
– This organizational structure was now outmoded.
Outmost: furthest away; farthest; furthest.
– The outmost reaches of the empire.
Outrageous: offensive and unacceptable; scandalous; disgraceful.
– Outrageous behaviour.
Outre: unusual and typically rather shocking; weird; outlandish; offbeat.
– The composer’s more outré harmonies.
Outrigged: rigged with a structure projecting from or over the side of a boat for various purposes; to prevent capsizing or to support an oarlock or to help secure a mast; rigged.
– In 1901 clinker outrigged eights with sliding seats were used.
Outright: complete and total; open and direct; out-and-out.
– She was the outright winner.
Outside: of, on or facing the outer side; external; outermost; outward.
– The outside walls are damp.
Outsized: larger than the usual size; oversized; enormous.
– An outsized desk.
Outspoken: saying exactly what you think, even if this shocks or offends people; blunt; straightforward.
– An outspoken opponent of the leader.
Outspread: spread out completely; expanded; unfolded.
– The bird soared high, with outspread wings.
Outstanding: extremely good; excellent; marvelous.
– An outstanding player.
Outstretched: stretched or spread out as far as possible; prolonged; protracted.
– She took her father’s outstretched hand.
Outward: connected with the way people or things seem to be rather than with what is actually true; exterior; external.
– Mark showed no outward signs of distress.
Oval: like an egg in shape; ovate; oviform.
– An oval face.
Ovarian: connected with the ovaries; ovarian artery; ovarian cyst.
– Ovarian cancer.
Ovate: shaped like an egg; ovate; oviform.
– The leaves are ovate.
Over: finished; at an end; concluded.
– When we got to the cinema, the film was over.
Overabundant: excessively abundant; boundless; disproportionate.
– We are bombarded with food advertising and an overabundant supply of high fat and high sugar foods.
Overactive: too active, especially so that they imagine things that are not true; frenzied; excited.
– She suffers from an overactive imagination.
Overaged: too old to be allowed to do a particular thing; superannuated; oversupply.
– They were disqualified after fielding two overaged players.
Overaggressive: excessively quarrelsome or belligerent; aggressive; combative.
– Overaggressive youth.
Overall: including all the things or people that are involved in a particular situation; general; comprehensive.
– There will be winners in each of three age groups, and one overall winner.
Overambitious: unsuccessful or likely to be unsuccessful because of needing too much effort, money or time; exaggerated; grandiose.
– Her plans were overambitious.
Overarm: an overarm throw of a ball is done by moving your arm backwards then lifting it high above your shoulder; overhand; overhanded.
– He threw the ball overarm.
Overbearing: trying to control other people in an unpleasant way; domineering; tyrannical.
– An overbearing parent.
Overblown: that is made to seem larger, more impressive or more important than it really is; exaggerated; grandiose.
– Overblown ambitions/egos.
Overbold: excessively bold; flagrant; glaring.
– Outlaws from the forests had grown overbold.
Overburdened: having too much to carry, contain, or deal with; exhausted; fatigued.
– We’re trying to stop development in areas with overburdened roads and schools.
Overbusy: excessively busy; officious; domineering.
– An overbusy schedule.
Overcareful: too careful; overcautious; impetuous.
– He is a bit overcareful with his investments.
Overcast: covered with clouds; not bright; overclouded.
– Today it will be dull and overcast.
Overcautious: too careful; cautious; timid.
– An overcautious lawyer.
Overconfident: too confident; cocksure; conceited.
– He is overconfident and cocky.
Overcritical: too critical; fault-finding; hypercritical.
– Continue to increase your skills, but do not be overcritical of your abilities.
Overcrowded: with too many people or things in it; congested; overloaded.
– Too many poor people are living in overcrowded conditions.
Overcurious: obsolete; too finicky or fastidious; too inquisitive.
– They were overcurious to find out who won the game.
Overdelicate: unduly or extremely delicate; choosy; discriminating.
– From the long eyebrows and sensitive mouth to the small hands and feet, everything about him was too much chiseled, overdelicate.
Overdressed: wearing clothes that are too formal or too smart for a particular occasion; attire; clothe.
– There was a much overdressed security guard on duty at the home.
Overdue: not paid, done, returned, etc. by the required or expected time; late; behind schedule.
– The rent is now overdue.
Overemotional: excessively or abnormally emotional; sloppy emotional; more than usual emotion.
– I remember a meeting the evening before when we got a bit overemotional.
Overenthusiastic: having or showing an excessive degree of enthusiasm; overly enthusiastic; passionate.
– They have some slightly overenthusiastic fans.
Overexcited: too excited and not behaving in a calm or sensible way; hyper; nervous.
– Don’t get the children overexcited just before bedtime.
Overfamiliar: exceedingly or excessively familiar; arrogant; foolhardy.
– The overfamiliar use of her Christian name was intentional.
Overfed: given too much food; rotund; chubby.
– He was overfed, he said, depleted, suffering from nervous exhaustion.
Overfond: overfond of somebody/something liking somebody/something too much; extroverted; easy-going.
– She persuaded her overfond young boyfriend to spend hundreds of pounds on the ring.
Overfull: excessively full; overflowing; congested; crowded.
– We were very tired and were overfull of undigested story and tangled chronology.
Overgenerous: giving too much of something; wasteful; extravagant.
– She is not overgenerous with praise.
Overgreedy: too greedy; excessively gluttonous; ravenous.
– Overgreedy lawyer.
Overgrown: covered with plants that have been allowed to grow wild and have not been controlled; colossal; excessive.
– The path was completely overgrown.
Overhand: an overhand throw of a ball is done by moving your arm backwards then lifting it high above your shoulder; overhanded; overarm.
– An overhand pitch.
Overhasty: done too soon or doing something too soon, especially without enough thought; ill-considered; imprudent.
– We were overhasty in making the choice.
Overhead: above your head; raised above the ground; aerial; elevated.
– Overhead power lines.
Overheated: too hot; scorching; fiery hot.
– Don’t sleep in an overheated room.
Overindulgent: allowing someone to have more of something enjoyable than is good for them; greedy; self-indulgent.
– He recalls seeing an overindulgent colleague arriving back at his office after lunch still holding a glass.
Overjealous: suspicious or unduly suspicious or fearful of being displaced by a rival; green-eyed; jealous distrustful; having or showing distrust.
– Overjealous girlfriend.
Overjoyed: extremely happy or pleased; delighted; ecstatic.
– He was overjoyed at my success.
Overladen: having too large or too heavy a load; overloaded; overstuffed.
– An overladen trolley.
Overland: across the land; by land, not by sea or by air; terrestrial; ashore.
– An overland route.
Overlarge: excessively large; too large big; large.
– Cheyenne was left with an overlarge town site, but with some real excuse for existence.
Overlying: placed on or over something else; superimposed; superjacent.
– An overlying image.
Overmodest: excessively modest; confused; coy.
– An overmodest young man.
Overmuch: too much; very much; overflow.
– They adapted to the new arrangements without overmuch fuss.
Overnice: excessively fussy or fastidious; choosy; discriminating.
– Mildred was overnice in regard to their father.
Overnight: happening during the night; for a night; happening suddenly or quickly.
– An overnight flight.
Overoptimistic: too confident that something will be successful; excessively cheery; overly confident.
– I’m not overoptimistic about my chances of getting the job.
Overpowering: very strong or powerful; irresistible; overwhelming.
– An overpowering smell of fish.
Overpriced: too expensive; costing more than it is worth; exaggerated; excessive.
– The drinks in the bar were all overpriced.
Overprotective: too anxious to protect somebody from being hurt, in a way that limits their freedom; possessive; jealous.
– Overprotective parents.
Overproud: excessively proud; cocky; superior.
– He was a bit overproud.
Overqualified: having more experience or training than is necessary for a particular job, so that people do not want to employ you; skilled; experienced.
– Overqualified applicant.
Overrefined: excessively delicate or refined; superfine; refined; cultivated.
– Overrefined dairy products.
Overripe: too ripe; decayed; degenerate.
– Overripe fruit.
Overseas: connected with foreign countries, especially those separated from your country by the sea or ocean; abroad; foreign.
– The firm is expanding into overseas markets.
Oversensitive: too easily upset or offended; touchy; emotional.
– She’s oversensitive to criticism.
Overserious: unduly or excessively serious; humorless; harsh.
– An overserious person.
Oversewn: sewn together with overhand stitches; overhand; hand-crafted; handmade.
– An oversewn carpet.
Oversexed: having stronger sexual desire than is usual; lustful; passionate.
– My husband has always been a bit oversexed.
Overshot: turned by water falling on to it from a channel; exceeded; surpassed.
– The plane overshot the runway.
Oversize: bigger than the normal size; too big; gigantic.
– She wore a pair of baggy jeans and an oversize T-shirt.
Oversized: bigger than the normal size; too big; colossal; enormous.
– Many children are being taught in oversized classes.
Oversolicitous: too solicitous; concerning one’s health; burning; clamant.
– The service was pleasant, but oversolicitous.
Overstrung: being in a tense state; edgy; jittery.
– He emphasized, with an overstrung urgency.
Oversubscribed: if an activity, service, etc. is oversubscribed, there are fewer places, tickets, etc. than the number of people who are asking for them; insufficient; scant.
– The popular secondary schools in the town are usually oversubscribed.
Oversuspicious: more suspicious than is necessary or normal; uncertain; unsure; wary.
– Her father was oversuspicious regarding her interest.
Overt: done in an open way and not secretly; undisguised; unconcealed.
– There was little overt support for the project.
Overvaliant: having or showing undue valor or boldness; bold; fearless; daring.
– A foolish overvaliant act.
Overweening: showing that you are too confident or proud; arrogant; proud.
– She is driven by overweening ambition.
Overweight: too heavy, in a way that may be unhealthy; chubby; rotund.
– She was only a few pounds overweight.
Overwhelming: very great or very strong; so powerful that you cannot resist it or decide how to react; enormous; immense.
– The evidence against him was overwhelming.
Overworked: made to work too hard or too much; overburden; oppress.
– Overworked nurses.
Overwrought: very worried and upset; excited in a nervous way; distraught.
– She was still a little overwrought.
Overzealous: showing too much energy or enthusiasm; demonstrative; fidgety.
– An overzealous fan ran onto the stage during the concert.
Oviform: rounded like an egg; egg-shaped; elliptic; elliptical; rounded.
– They are evergreen compact epiphytes with an upright, narrow, oviform leaves.
Ovine: relating to sheep; sheepish; flexile.
– Someone who shears sheep gives ovine haircuts.
Oviparous: producing eggs rather than live babies; live-bearing.; viviparous.
– It is an oviparous animal, and its eggs scarcely exceed in size those of a goose.
Ovoid: like an egg in shape; ellipsoidal; elliptic.
– An ovoid body.
Ovoviviparous: producing babies by means of eggs that are hatched inside the body of the parent, like some snakes; gg-laying; broody.
– Ovoviviparous is producing eggs that develop within the maternal body and hatch.
Owing: money that is owing has not been paid yet; unpaid; unsettled.
– £100 is still owing on the loan.
Owlish: looking like an owl, especially because you are wearing round glasses, and therefore seeming serious and intelligent; nearsighted; myopic.
– He was an owlish figure, sitting in the corner of the library.
Own: used to emphasize that something belongs to or is connected with somebody; keep; retain.
– It was her own idea.
Owned: having an owner; often used in combination; closely-held.
– State owned railways.
Ownerless: having no owner; unowned; desolate.
– Many of the biggest corporations do seem ownerless, answerable to no one.
Oxidative: taking place in the presence of oxygen; aerobic; aerophilic.
– Oxidative rancidity.
Oxidised: combined with or having undergone a chemical reaction with oxygen; oxidized; powdery.
– Iron is easily oxidized.
Oxidizable: capable of undergoing a chemical reaction with oxygen; reactive; participating readily in reactions.
– Organic oxidizable carbon was also observed in the forest soils.
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