shorttail weasel vs weasel

shorttail weasel and weasel both are nouns.

Word	Noun	Adjective	Verb	Adverb
shorttail weasel	Yes	No	No	No
weasel	Yes	No	No	No

As nouns, weasel is a hypernym of shorttail weasel; that is, weasel is a word with a broader meaning than shorttail weasel:

shorttail weasel: mustelid of Northern Hemisphere in its white winter coat
weasel: small carnivorous mammal with short legs and elongated body and neck

shorttail weasel (noun)	weasel (noun)
mustelid of Northern Hemisphere in its white winter coat	small carnivorous mammal with short legs and elongated body and neck
	a person who is regarded as treacherous or sneaky