withstander vs antagonist

withstander and antagonist both are nouns.

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

As nouns, antagonist is a hypernym of withstander; that is, antagonist is a word with a broader meaning than withstander:

Other hypernyms of withstander include adversary, opponent, opposer, resister.

withstander (noun)	antagonist (noun)
an opponent who resists with force or resolution	a drug that neutralizes or counteracts the effects of another drug
a fighter who holds out against attack	a muscle that relaxes while another contracts
	someone who offers opposition