Trifle with beautiful woman holding a gun (9)
I believe the answer is:
bagatelle
'trifle' is the definition.
(thesaurus)
'beautiful woman holding a gun' is the wordplay.
'beautiful woman' becomes 'belle' (I've seen this before).
'holding' indicates putting letters inside.
'gun' becomes 'gat' (gat is a kind of gun).
'a'+'gat'='agat'
'belle' placed around 'agat' is 'BAGATELLE'.
'with' is the link.
(Other definitions for bagatelle that I've seen before include "Something trivial" , "Board-game, trifle" , "Musical item" , "game at the tables?" , "no serious work" .)