What is another word for "antagonist"?

Roget's Thesaurus (1911) lists these synonyms for "antagonist": adversary, adverse, against, assailant, back, being, bete, bitter, brangler, brawler, can, competitor, demagogue, disputant, enemy, every, filibuster, foe, foeman, friend, from, hand, like, made, malcontent, myself, needs, never, obstructionist, obstructive, one, open, opponent, opposition, oppositionist, other, party, protect, public, reactionist.