Animal related to the stoat (6)
I believe the answer is:
weasel
'animal related to the stoat' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for weasel that I've seen before include "Carnivore (with evasive words)" , "Small mammal with short legs and long body and neck" , "This small mammal saw eel" , "Sly type" , "Sly character" .)