KEY: Reason \.\\.
SYN: Ground, account, cause, explanation, motive, proof, apology,understanding, reasoning, rationality, right, propriety, justice,order, object, sake, purpose.
ANT: Pretext, pretence, misinterpretation, falsification,misconception, disproof, unreasonableness, absurdity, fallacy,irrationality, wrong, unreason, impropriety, unfairness, folly,aimlessness, unaccountableness.

• Omit
• Omnipotent
• Omniscient
• One
• Oneness, [See UNITY]
• Onerous
• Only_\a
• Only, adv
• Onset, [See ATTACK]
• Onslaught, [See ATTACK]
• Onward
• Ooze
• Opaque, [See TRANSPARENT]
• Open_\a
• Opening
• Open_\r
• Operate
• Operation
• Operative
• Operose
• Opine
• Opinion
• Opinionative
• Opponent, [See ADVERSARY]
• Opportune