Brown ermine (5)
I believe the answer is:
stoat
'brown ermine' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for stoat that I've seen before include "Small carnivore" , "Ermine in summertime?" , "Source of ermine" , "Short-tail weasel" , "Provider of ermine" .)