opponent
n.
1580s, from Latin opponentem (nominative opponens), present participle of opponere "oppose, object to," literally "set against, set opposite," from ob "against" (see ob-) + ponere "to put, set, place" (see position, n.).
〔蒋〕[op-=ob-相反，相对，pon放置，-ent形容词后缀，…的;’置于相反位置上的”] 对立的，对抗的;[-ent表示人] 对手，敌手