Horse color (4)
I believe the answer is:
roan
'horse color' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for roan that I've seen before include "Type of 17's coat colouring" , "Horse with a brownish coat sprinkled with grey" , "Horse with coat speckled with white or grey" , "Horse with brownish coat speckled with white" , "Horse with main colour interspersed with hairs of another" .)