Basque topper (5)
I believe the answer is:
beret
'basque topper' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for beret that I've seen before include "Soft round cap without a peak" , "Felt hat" , "felt on one's head" , "cover for commandos" , "Soft peak-less kind of cap" .)