antagonism vs antagonistic

antagonism is a noun but antagonistic is not a noun.

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

antagonism (noun)	antagonistic (noun)
(biochemistry) interference in or inhibition of the physiological action of a chemical substance by another having a similar structure
an actively expressed feeling of dislike and hostility
the relation between opposing principles or forces or factors
a state of deep-seated ill-will

antagonism (adjective)	antagonistic (adjective)
	arousing animosity or hostility
	used especially of drugs or muscles that counteract or neutralize each other's effect
	characterized by antagonism or antipathy
	incapable of harmonious association
	indicating opposition or resistance