Domesticated polecat (6)
I believe the answer is:
ferret
'domesticated polecat' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ferret that I've seen before include "It's used to drive rabbits from their holes" , "Animal used to catch rabbits" , "Find (out) by persistent investigation" , "Tame polecat" , "Type of polecat -- or silk binding tape" .)