Herald's tunic (6)
I believe the answer is:
tabard
'herald's tunic' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for tabard that I've seen before include "Sleeveless jerkin" , "Knight's outer tunic" , "Inn where pilgrims met" , "Jacket worn by a herald" , "Herald's coat or tunic" .)