Servant's uniform (6)
I believe the answer is:
livery
'servant's uniform' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for livery that I've seen before include "Horse maintenance" , "Uniform worn by male servants" , "The care of horses for pay" , "old servants" , "Distinctive uniform once worn by servants of posh people" .)