Synonyms and Antonyms Starting with Letter O! One way to improve your English vocabulary is by studying synonyms and antonyms of words. Here are some common English words starting with the letter O, along with their synonyms and antonyms.
- Obey: to comply with or follow (a rule, order, or request).
Synonyms: comply with, adhere to, conform to.
Antonyms: defy, disobey, flout.
- Occupy: to take up or fill (time, space, etc.).
Synonyms: fill, take up.
Antonyms: empty, vacate.
Synonyms and Antonyms Starting with Letter O
| Sr. | Words | Synonyms | Antonyms |
| 1 | Obliging | complaisant, willing | mulish, obstinate |
| 2 | Oblivious | unconscious, preoccupied, dazed | mindful, aware |
| 3 | Obnoxious | offensive, abominable, repulsive | pleasant, pleasing |
| 4 | Obscure | arcane, vague | prominent |
| 5 | Observe | examine, study, scrutinize | ignore, disregard |
| 6 | Obsolete | extinct, dated, antiquated | stylish, vogue, current |
| 7 | Obstinate | stubborn, adamant | pliable, flexible |
| 8 | Obstruct | impede, prevent | hasten, encourage |
| 9 | Obtain | access, inherit | forfeit |
| 10 | Obvious | evident, apparent | obscure, ambiguous |
| 11 | Occult | latent, ambiguous | intelligible, transparent |
| 12 | Odd | peculiar, weird, strange | usual, ordinary |
| 13 | Odious | malevolent, obnoxious | engaging, fascinating |
| 14 | Offend | displease, affront, disgust | please, delight |
| 15 | Offensive | abhorrent, obnoxious | engaging, fascinating |
| 16 | Offspring | descendant, sibling | ancestor, forefather |
| 17 | Ominous | menacing, foreboding | auspicious |
| 18 | Opaque | obscure, shady | transparent, bright |
| 19 | Open | begin, unfold, originate | close |
| 20 | Opponent | enemy, rival, foe | ally, friend |
| 21 | Optimist | idealist | pessimist |
| 22 | Optimistic | hopeful, confident | pessimistic |
| 23 | Optional | voluntary, elective | required |
| 24 | Oracular | cryptic, vague | lucid, distinct |
| 25 | Ordain | order, impose | revoke abolish |
| 26 | Ordinary | usual, average | unusual, remarkable |
| 27 | Ornamental | decorative, adorned | unseemly, plain |
| 28 | Outbreak | eruption, insurrection | compliance, subjection |
| 29 | Outrage | offense, maltreatment | praise, favor |
| 30 | Outrageous | preposterous, shocking | warranted, acceptable |
| 31 | Outstanding | extraordinary, distinguished | insignificant, inconsequential |
