An‐tag″o‐nist (ăn‐tăg″ō̍‐nĭst), n. [L. antagonista, Gr. ανταγωνιστἤσ; αντἴ against + αγωνιστἤσ combatant, champion, fr. αγωνἴζεσθαι: cf. F. antagoniste. See Antagonism.] 1. One who contends with another, especially in combat; an adversary; an opponent.
Antagonist of Heaven's Almighty King.
Milton.
Our antagonists in these controversies.
Hooker.
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.
3. (Med.) A medicine which opposes the action of another medicine or of a poison when absorbed into the blood or tissues.
Syn. — Adversary; enemy; opponent; toe; competitor. See Adversary.