caprine animal vs billy

caprine animal and billy both are nouns.

Word	Noun	Adjective	Verb	Adverb
caprine animal	Yes	No	No	No
billy	Yes	No	No	No

As nouns, billy is a hyponym of caprine animal; that is, billy is a word with a more specific, narrower meaning than caprine animal:

caprine animal: any of numerous agile ruminants related to sheep but having a beard and straight horns
billy: male goat

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

caprine animal (noun)	billy (noun)
any of numerous agile ruminants related to sheep but having a beard and straight horns	male goat
	a short stout club used primarily by policemen