WordReference Random House Unabridged Dictionary of American English © 2017
- a person engaged in a contest, conflict, struggle, etc., esp. the protagonist in a literary work.
- a person who is torn by inner conflict.
- Physiologya contracting muscle whose action is opposed by another muscle. Cf. antagonist (def. 3).
- Drugs[Pharm.]a chemical substance capable of activating a receptor to induce a full or partial pharmacological response. Cf. antagonist (def. 5).
- Greek agōnisté̄s contestant, equivalent. to agó̄n agon + -istēs -ist
- Late Latin agōnista