white tail vs cervid

white tail and cervid both are nouns.

Word	Noun	Adjective	Verb	Adverb
white tail	Yes	No	No	No
cervid	Yes	No	No	No

As nouns, cervid is a hypernym of white tail; that is, cervid is a word with a broader meaning than white tail:

white tail: common North American deer; tail has a white underside
cervid: distinguished from Bovidae by the male's having solid deciduous antlers

Other hypernyms of white tail include deer.

white tail (noun)	cervid (noun)
common North American deer; tail has a white underside	distinguished from Bovidae by the male's having solid deciduous antlers