agonist vs agonistic

agonist is a noun but agonistic is not a noun.

Word	Noun	Adjective	Verb	Adverb
agonist	Yes	No	No	No
agonistic	No	Yes	No	No

agonist (noun)	agonistic (noun)
(biochemistry) a drug that can combine with a receptor on a cell to produce a physiological reaction
a muscle that contracts while another relaxes
someone involved in a contest or battle (as in an agon)
the principal character in a work of fiction

agonist (adjective)	agonistic (adjective)
	of or relating to the athletic contests held in ancient Greece
	struggling for effect
	striving to overcome in argument