Polecat

Polecat is the common name for several medium-sized cat-like mustelids. They don’t form a single clade: the name is given to several similar species. And the name is said to have possibly either come from an Old French word poule meaning chicken, and the English word cat, or from a shift from a compound of pole + cat, in reference to its prey on chickens, its long pole-like body, and cat-like appearance. 

The European polecat is typical, and is the only one native to the British Isles. Ferrets are the domesticated form of European polecats.

In the U.S., the term polecat is often applied to skunks, which are only distantly related to the European polecat. The reason is that polecats give off a scent which some people think is offensive. 

 Taxonomy 
The simplest version puts them all in a subfamily of the Mustelidae:

Subfamily Mustelinae
Genus Ictonyx
Striped polecat, I. striatus
Saharan striped polecat, I. libycus
Genus Mustela
Steppe polecat, M. eversmannii
American polecat (Black-footed ferret) M. nigripes
European polecat, M. putorius
Genus Vormela
Marbled polecat, V. peregusna

There is a more recent version which splits them up even more.

References

Category:Mustelids