ermine vs weasel

ermine and weasel both are nouns.

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

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

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

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