goat vs nanny-goat

goat and nanny-goat both are nouns.

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

As nouns, nanny-goat is a hyponym of goat; that is, nanny-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
nanny-goat: female goat

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

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