Distinctive uniform (6)
I believe the answer is:
livery
'distinctive uniform' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for livery that I've seen before include "Uniform -- suffering from gastric distress" , "The stabling and care of horses" , "Irritable" , "The care of horses for pay" , "Distinctive uniform once worn by servants of posh people" .)