wild ass vs ass

wild ass and ass both are nouns.

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

As nouns, ass is a hypernym of wild ass; that is, ass is a word with a broader meaning than wild ass:

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

wild ass (noun)	ass (noun)
any of several equine mammals of Asia and northeast Africa	slang for sexual intercourse
	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