Swagger in clothes making a comeback (4)
I believe the answer is:
brag
'swagger' is the definition.
(thesaurus)
'clothes making a comeback' is the wordplay.
'clothes' becomes 'garb' (garb is a kind of clothes).
'making a comeback' shows that the letters should be reversed in order.
'garb' in reverse letter order is 'BRAG'.
'in' acts as a link.
(Other definitions for brag that I've seen before include "Boast, crow" , "game of bluff" , "Blow one's own trumpet" , "'Show off, boast (4)'" , "boast; form of poker" .)