Female improperly cut this film on traitor (5,9)
I believe the answer is:
fifth columnist
'traitor' is the definition.
(I've seen this before)
'female improperly cut this film on' is the wordplay.
'female' becomes 'f' (abbreviation).
'improperly' indicates anagramming the letters (I've seen this in other clues).
'cut'+'this'+'film'+'on'='cutthisfilmon'
'cutthisfilmon' with letters rearranged gives 'ifthcolumnist'.
'f'+'ifthcolumnist'='FIFTH COLUMNIST'
(Other definitions for fifth columnist that I've seen before include "Enemy agent" , "infiltrator!" , "addition to quartet of writers?" , "Traitor" , "Subversive" .)