antagonist vs antagonism

antagonist and antagonism both are nouns.

Word	Noun	Adjective	Verb	Adverb
antagonist	Yes	No	No	No
antagonism	Yes	No	No	No

antagonist (noun)	antagonism (noun)
a drug that neutralizes or counteracts the effects of another drug	(biochemistry) interference in or inhibition of the physiological action of a chemical substance by another having a similar structure
a muscle that relaxes while another contracts	an actively expressed feeling of dislike and hostility
someone who offers opposition	the relation between opposing principles or forces or factors
	a state of deep-seated ill-will