antagonistic vs antagonist

antagonistic is not a noun while antagonist is a noun.

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

antagonistic (noun)	antagonist (noun)
	a drug that neutralizes or counteracts the effects of another drug
	a muscle that relaxes while another contracts
	someone who offers opposition

antagonistic (adjective)	antagonist (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