antagonist

nouns

someone who offers opposition
is derived from
is derived from
is derived from
is derived from
antonym
a muscle that relaxes while another contracts
"when bending the elbow the triceps are the antagonist"
is derived from
is a type of (narrower)
(physiology) a muscle that opposes the action of another
"the biceps and triceps are antagonistic muscles"
a drug that neutralizes or counteracts the effects of another drug
is derived from
is derived from
antonym
is a type of (narrower)
a substance that is used as a medicine or narcotic