36 Adjectives That Start With "O"
36 curated adjectives that start with "O".
Below are 36 adjectives that start with "O" in our curated English dictionary. Each entry includes a learner-friendly definition, IPA pronunciation, CEFR difficulty level, and example sentences. Words are sorted by frequency — the most common first. Click any word to view its full dictionary entry with synonyms, collocations, and common mistakes.
Most Common Adjectives That Start With "O" (Top 1k)
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Obvious /ˈɒbviəs/adj A2
Easy to see or understand; not hidden or difficult.
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Ok /ˌoʊˈkeɪ/adj A1
Good enough; not bad, but not great.
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Old /oʊld/adj A1
Having been alive or existing for a long time.
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Open /ˈoʊpən/adj A1
Not covered or closed; you can go in or see inside.
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Original /əˈrɪdʒənəl/adj B1
The first version; something new and different from copies.
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Other /ˈʌðər/adj A1
Something different or extra from what you already have.
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Our /ˈaʊər/adj A1
Shows that something belongs to or is part of a group that includes you.
Less Common Adjectives That Start With "O" (Top 5k+)
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Objective /əbˈdʒɛktɪv/adj B2
Using facts and evidence, not personal beliefs. An objective assessment considers only data, not emotions.
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Official /əˈfɪʃəl/adj A2
Approved by someone in power or authority.
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Online /ˌɑnˈlaɪn/adj B1
Working through the internet; available on computers.
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Opposite /ˈɑːpəzɪt/adj A1
Something that is totally different or on the other end of something.
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Optimal /ˈɒptɪməl/adj B2
Achieving the very best result or condition for a specific situation.
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Ordinary /ˈɔːrdəneri/adj A2
Usual or everyday; nothing unusual or special about it.
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Organic /ɔːrˈɡænɪk/adj B1
Food grown without artificial chemicals or harmful treatments; made the natural way without factory-made pesticides.
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Outdoor /ˈaʊtdɔːr/adj A2
Outside. Not inside a house or building. Happening in nature or fresh air.
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Overdue /ˌoʊvərˈduː/adj B1
Late; expected to arrive or be finished by now but has not happened yet.
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Overt /oʊˈvɜːrt/adj C2
Something that is open and honest, done in a way everyone can see. The opposite of hidden or secret.
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Obsolete /ˈɑːbsəliːt/adj C1
Old and no longer used because something newer has replaced it. Not fashionable or practical anymore.
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Occupational /ˌɒkjuˈpeɪʃənəl/adj C1
About the type of job someone has or the work they do every day. Related to their profession.
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Ongoing /ˈɑːnɡoʊɪŋ/adj B2
Something that is still happening now and continues to happen. Not yet finished or ended.
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Open-source /ˌoʊpən ˈsɔːrs/adj B2
Software whose code is available to everyone to view, change, and share freely.
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Orthodox /ˈɔːrθədɒks/adj C1
Following the traditional or standard way that most people accept. Not new or different.
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Outmoded /ˌaʊtˈmoʊdɪd/adj C1
Gone out of fashion or style. Nobody uses or likes this way of doing things anymore. It's been replaced by something newer.
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Outstanding /aʊtˈstændɪŋ/adj B2
Very good or impressive. Or something that has not been finished or paid.
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Overarching /ˌoʊvərˈɑːrʃɪŋ/adj C1
Covering everything important; the biggest or most important thing that includes all the others under it.
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Overdrawn /ˌoʊvərˈdrɔːn/adj B2
When your bank account has a negative balance because you took out more money than you had.
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Overwhelming /ˌoʊvərˈwelmɪŋ/adj B2
So much of something (emotion, work, numbers) that you feel completely unable to cope. It's too much to handle.
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Obscure /əbˈskjʊr/adj C2
Not clear or easy to understand; unclear and ambiguous; also, not well-known or famous; dim and hard to see.
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Obsequious /əbˈsiːkwiəs/adj C2
Too eager to please or obey; showing excessive respect or flattery in an insincere way.
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Omnipotent /ɒmˈnɪpətənt/adj C2
Having unlimited power; able to do anything imaginable without restriction or limit.
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Omnipresent /ˌɒmnɪˈprezənt/adj C2
Presence everywhere simultaneously
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Omniscient /ɒmˈnɪʃənt/adj C2
Knowing absolutely everything; aware of all facts past, present, and future without limits.
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Opaque /oʊˈpeɪk/adj C2
Not letting light through; not transparent; also, not clear or easy to understand; hard to see through or comprehend.
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Opulent /ˈɑːpjələnt/adj C2
Very luxurious and expensive-looking; richly decorated with expensive materials; showing abundance and wealth.
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Ostensible /ɒˈstɛnsəbəl/adj C2
Appears to be one thing on the surface, but might actually be different underneath. What you see is not necessarily what is really happening.
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Ostentatious /ɒstenˈteɪʃəs/adj C2
Describing something that is deliberately showy, flashy, or excessive in order to impress people; appearing important or valuable in an artificial way.
How to Use Adjectives That Start With "O"
Adjectives that start with "O" let you describe nouns with precision. Use comparative forms ("-er than" or "more …") when comparing two things, and superlative forms ("the …-est" or "the most …") when ranking three or more. Short adjectives usually take "-er/-est"; longer ones use "more/most". Several adjectives in this list are also gradable — modify them with "very", "quite", or "extremely" to fine-tune meaning.
Longest Adjective That Start With "O"
About the type of job someone has or the work they do every day. Related to their profession.
Frequently Asked Questions About Adjectives That Start With "O"
- How many adjectives that start with "O"?
- Our curated dictionary lists 36 adjectives that start with "O", each with a definition, IPA, CEFR level, and example sentences. The list grows as new entries are reviewed.
- What are the most common adjectives that start with "O"?
- Some of the most frequent adjectives that start with "O" include OBVIOUS, OK, OLD, OPEN, ORIGINAL. These appear in everyday English and are useful for both beginners (A1-A2) and intermediate learners.
- What is adjective?
- An adjective is a word that describes or modifies a noun, telling us about its qualities, quantity, or condition. Adjectives usually appear before the noun or after a linking verb.
- What is the longest adjective that start with "O"?
- The longest adjective that start with "O" in our dictionary is "OCCUPATIONAL" (12 letters). Tap the word to see its full entry.