Musteline mammal (7)
I believe the answer is:
polecat
'musteline mammal' is the definition.
(I know that polecat is a type of musteline mammal)
This is all the clue.
(Other definitions for polecat that I've seen before include "Kind of weasel, called skunk in America" , "weaselly creature" , "Malodorous carnivore" , "weaselly type" , "Smelly American mammal" .)