goat vs he-goat

goat and he-goat both are nouns.

Word	Noun	Adjective	Verb	Adverb
goat	Yes	No	No	No
he-goat	Yes	No	No	No

As nouns, he-goat is a hyponym of goat; that is, he-goat is a word with a more specific, narrower meaning than goat:

goat: any of numerous agile ruminants related to sheep but having a beard and straight horns
he-goat: male goat

Other hyponyms of goat include kid, billy, billy goat, nanny-goat, nanny, she-goat, Capra hircus, domestic goat, wild goat.

goat (noun)	he-goat (noun)
any of numerous agile ruminants related to sheep but having a beard and straight horns	male goat
a victim of ridicule or pranks