Domesticated polecat (6)
I believe the answer is:
ferret
'domesticated polecat' is the definition.
(I've seen this before)
This is the entire 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" .)