Origin: 1580–90; < Latin oppōnent- (stem of oppōnēns, present participle of oppōnere to place over, against, or in front of, make an obstacle), equivalent to op-op- + pōn(ere) to place, set, put + -ent--ent
Synonyms 1. antagonist. Opponent,competitor,rival refer to persons engaged in a contest. Opponent is the most impersonal, meaning merely one who opposes; perhaps one who continually blocks and frustrates or one who happens to be on the opposite side in a temporary contest: an opponent in a debate. Competitor emphasizes the action in striving against another, or others, for a definite, common goal: competitors in business. Rival has both personal and emotional connotations; it emphasizes the idea that (usually) two persons are struggling to attain the same object: rivals for an office.
1588, from L. opponentem (nom. opponens), prp. of opponere "oppose, object to, set against," from ob "against" + ponere "to put, set, place" (see position).