epos vs poesy

epos and poesy both are nouns.

Word	Noun	Adjective	Verb	Adverb
epos	Yes	No	No	No
poesy	Yes	No	No	No

As nouns, poesy is a hypernym of epos; that is, poesy is a word with a broader meaning than epos:

epos: a body of poetry that conveys the traditions of a society by treating some epic theme
poesy: literature in metrical form

Other hypernyms of epos include poetry, verse.

epos (noun)	poesy (noun)
a long narrative poem telling of a hero's deeds	literature in metrical form
a body of poetry that conveys the traditions of a society by treating some epic theme