n. [ L. antagonista, Gr. 'antagwnisth`s; 'anti` against + 'agwnisth`s combatant, champion, fr. 'agwni`zesqai: cf. F. antagoniste. See Antagonism. ] 1. One who contends with another, especially in combat; an adversary; an opponent. [ 1913 Webster ]
Antagonist of Heaven's Almighty King. Milton. [ 1913 Webster ]
Our antagonists in these controversies. Hooker. [ 1913 Webster ]
2. (Anat.) A muscle which acts in opposition to another; as a flexor, which bends a part, is the antagonist of an extensor, which extends it. AS [ 1913 Webster ]
3. (Med.) A substance which opposes the actions of another substance in the body, especially a drgu that counteracts the effects of another drug. [ 1913 Webster + AS ]
Syn. -- Adversary; enemy; opponent; foe; competitor. See Adversary. [ 1913 Webster ]