Comb horse – starts to look elegant (6)
I believe the answer is:
hackle
'comb' is the definition.
(I know that hackle is a kind of comb)
'horse starts to look elegant' is the wordplay.
'horse' becomes 'hack' (hack is a kind of horse).
'starts to' suggests taking the first letters.
The initial letters of 'look elegant' is 'le'.
'hack'+'le'='HACKLE'
(Other definitions for hackle that I've seen before include "Feather forming part of an angler's fly" , "Feather wound around a fishing fly" .)