antagonist

[ an-tag-uh-nist ]
/ ænˈtæg ə nɪst /

noun

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.

Origin of antagonist

1590–1600; < Late Latin antagōnista < Greek antagōnistḗs. See antagonize, -ist

Can be confused

antagonist proponent protagonist

Synonym study

1. See adversary.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for antagonist

British Dictionary definitions for antagonist

antagonist

/ (ænˈtæɡənɪst) /

noun

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

Medicine definitions for antagonist

antagonist

[ ăn-tăgə-nĭst ]

n.

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.

Science definitions for antagonist

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.