Flaming felony (5)
I believe the answer is:
arson
'flaming felony' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for arson that I've seen before include "Be pettish" , "Sonar (anag.)" , "major crime" , "Crime of fire-setting (5)" , "Crime of fire raising" .)