antagonist has definitions from the fields of anatomy,zoology,pharmacology
1
[ noun ] someone who offers opposition

Used in print

(Richard F. McLaughlin, et al., "A study of the...)

Miller ( ' 50 ) is the principal antagonist of this viewpoint .

2
[ noun ] (pharmacology) a drug that neutralizes or counteracts the effects of another drug
3
[ noun ] (anatomy,zoology) a muscle that relaxes while another contracts

Examples

"when bending the elbow the triceps are the antagonist"

Related terms

antagonistic_muscle

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