Animal wearing crude ermine (4)
I believe the answer is:
deer
'animal' is the definition.
(deer is a type of animal)
'wearing crude ermine' is the wordplay.
'wearing' indicates a hidden word (the answer is covered by or 'wearing' the clue).
'DEER' is hidden in the letters of 'crude ermine'.
(Other definitions for deer that I've seen before include "See 23" , "Antler-bearing animal" , "does for example" , "Like a power switch" , "Source of venison" .)