Deer performs (4)
I believe the answer is:
does
I believe this clue is a double definition.
'deer' is the first definition.
(I've seen this in other clues)
'performs' is the second definition.
(to do something is to perform or execute it)
(Other definitions for does that I've seen before include "Female deers" , "Acts" , "Suffices" , "Performs; female animals" , "takes one for a ride" .)