ass vs wild ass

ass and wild ass both are nouns.

Word	Noun	Adjective	Verb	Adverb
ass	Yes	No	No	No
wild ass	Yes	No	No	No

As nouns, wild ass is a hyponym of ass; that is, wild ass is a word with a more specific, narrower meaning than ass:

ass: hardy and sure-footed animal smaller and with longer ears than the horse
wild ass: any of several equine mammals of Asia and northeast Africa

Other hyponyms of ass include domestic ass, donkey, Equus asinus, jack, jackass, jennet, jenny, jenny ass.

ass (noun)	wild ass (noun)
slang for sexual intercourse	any of several equine mammals of Asia and northeast Africa
hardy and sure-footed animal smaller and with longer ears than the horse
the fleshy part of the human body that you sit on
a pompous fool