Swagger from supporter with trouble after victory (7)
I believe the answer is:
bravado
'swagger' is the definition.
(thesaurus)
'supporter with trouble after victory' is the wordplay.
'supporter' becomes 'bra' (I've seen this before).
'with' means one lot of letters go next to another.
'trouble' becomes 'ado' (I've seen this before).
'after' means one lot of letters go next to another.
'victory' becomes 'v'.
'ado' after 'v' is 'vado'.
'bra' put next to 'vado' is 'BRAVADO'.
'from' is the link.
(Other definitions for bravado that I've seen before include "Bottle" , "front" , "Swag" , "Swaggering show of boldness" , "Boastfulness" .)