Bagpiper's garb (4)
I believe the answer is:
'bagpiper's garb' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for kilt that I've seen before include "Scottish costume" , "Scots dress" , "Highland garment" , "Knee-length tartan garment" , "Scotsman's garb" .)