Mustelid and Polecat

Mustelid noun - Fissiped fur-bearing carnivorous mammals.

Polecat and mustelid are semantically related. In some cases you can replace term "Polecat" with "Mustelid", this nouns are similar.

Polecat noun - American musteline mammal typically ejecting an intensely malodorous fluid when startled; in some classifications put in a separate subfamily Mephitinae.

Mustelid and polecat are semantically related. You can use "Mustelid" instead a noun "Polecat".