[ an-tag-uh-nist ]
/ ænˈtæg ə nɪst /
Save This Word!


a person who is opposed to, struggles against, or competes with another; opponent; adversary.
the adversary of the hero or protagonist of a drama or other literary work: Iago is the antagonist of Othello.
Physiology. a muscle that acts in opposition to another.Compare agonist (def. 3).
Dentistry. a tooth in one jaw that articulates during mastication or occlusion with a tooth in the opposing jaw.
Pharmacology. a drug that counteracts the effects of another drug.Compare agonist (def. 4).



In effect, this quiz will prove whether or not you have the skills to know the difference between “affect” and “effect.”
Question 1 of 7
The rainy weather could not ________ my elated spirits on my graduation day.

Origin of antagonist

First recorded in 1590–1600; from Late Latin antagōnista, from Greek antagōnistḗs. See antagonize, -ist
1. See adversary.
antagonist , protagonist
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021

British Dictionary definitions for antagonist

/ (ænˈtæɡənɪst) /


an opponent or adversary, as in a contest, drama, sporting event, etc
any muscle that opposes the action of anotherCompare agonist (def. 1)
a drug that counteracts the effects of another drugCompare synergist (def. 1)
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for antagonist

[ ăn-tăgə-nĭst ]


Something, such as a muscle, disease, or physiological process, that neutralizes or impedes the action or effect of another.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Scientific definitions for antagonist

[ ăn-tăgə-nĭst ]

A muscle that opposes the action of another muscle, as by relaxing while the other one contracts, thereby producing smooth, coordinated movement.
A chemical substance, such as a drug, that interferes with the physiological action of another substance, especially by combining with and blocking its nerve receptor. Compare agonist.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Learn A New Word Right Now!