equid vs ass

equid and ass both are nouns.

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

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

equid: hoofed mammals having slender legs and a flat coat with a narrow mane along the back of the neck
ass: hardy and sure-footed animal smaller and with longer ears than the horse

Other hyponyms of equid include Equus caballus, horse, mule, hinny, zebra, Equus quagga, quagga.

equid (noun)	ass (noun)
hoofed mammals having slender legs and a flat coat with a narrow mane along the back of the neck	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