Boast about one's apparel (4)
I believe the answer is:
garb
'one's apparel' is the definition.
'garb' can be an answer for 'apparel' (garb is a kind of apparel). I'm not sure about the 'one's' bit.
'boast about' is the wordplay.
'boast' becomes 'brag' (synonyms).
'about' shows that the letters should be reversed in order.
'brag' in reverse letter order is 'GARB'.
Can you help me to learn more?
(Other definitions for garb that I've seen before include "Kit" , "Dress - clothing" , "Covering" , "gear discovered" , "Clothe" .)