Cash in on the act? (7)
I believe the answer is:
exploit
I believe this is a double definition.
'cash in on' is the first definition.
(thesaurus)
'the act?' is the second definition.
(exploit is a kind of act)
(Other definitions for exploit that I've seen before include "Make good or selfish use of" , "The deed to make gain from" , "Bunk" , "Feat; make use of" , "Make use of - great deed" .)