Bravado deserted guilty party (7-2)
I believe the answer is:
derring-do
'bravado' is the definition.
(thesaurus)
'deserted guilty party' is the wordplay.
'deserted' becomes 'd'.
'guilty' becomes 'erring' (erring means going wrong).
'party' becomes 'do' (do is a kind of party).
'd'+'erring'+'do'='DERRING-DO'
(Other definitions for derring-do that I've seen before include "Literary word for heroic courage or action" , "Brave and heroic feat(s)" , "heroic deeds" , "Courageous action" , "Daring deeds" .)