Small carnivorous mammal of the weasel family (5)
I believe the answer is:
stoat
'small carnivorous mammal of the weasel family' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for stoat that I've seen before include "Member of the weasel family" , "Small carnivore" , "Small carnivorous mammal of the weasel family" , "Source of ermine" , "Weasel, ermine" .)