foe vs antagonist

foe and antagonist both are nouns.

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

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

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

foe (noun)	antagonist (noun)
a personal enemy	a drug that neutralizes or counteracts the effects of another drug
an armed adversary (especially a member of an opposing military force)	a muscle that relaxes while another contracts
	someone who offers opposition