polecat vs mustelid

polecat and mustelid both are nouns.

Word	Noun	Adjective	Verb	Adverb
polecat	Yes	No	No	No
mustelid	Yes	No	No	No

As nouns, mustelid is a hypernym of polecat; that is, mustelid is a word with a broader meaning than polecat:

polecat: dark brown mustelid of woodlands of Eurasia that gives off an unpleasant odor when threatened
mustelid: fissiped fur-bearing carnivorous mammals

Other hypernyms of polecat include musteline, musteline mammal.

As nouns, mustelid is a hypernym of polecat; that is, mustelid is a word with a broader meaning than polecat:

polecat: American musteline mammal typically ejecting an intensely malodorous fluid when startled; in some classifications put in a separate subfamily Mephitinae
mustelid: fissiped fur-bearing carnivorous mammals

Other hypernyms of polecat include musteline, musteline mammal.

polecat (noun)	mustelid (noun)
dark brown mustelid of woodlands of Eurasia that gives off an unpleasant odor when threatened	fissiped fur-bearing carnivorous mammals
American musteline mammal typically ejecting an intensely malodorous fluid when startled; in some classifications put in a separate subfamily Mephitinae