Brag about attire (4)
I believe the answer is:
garb
'attire' is the definition.
(both can mean clothing)
'brag about' is the wordplay.
'about' shows that the letters should be reversed in order.
'brag' back-to-front is 'GARB'.
(Other definitions for garb that I've seen before include "something to wear" , "Dress - clothing" , "Clothe" , "Apparel, attire" , "Dress - habit" .)