Roulette bet (4)
I believe the answer is:
noir
'roulette bet' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for noir that I've seen before include "film genre" , "Film featuring bleak settings and cynical characters" , "type of film" , "(Of film or fiction) with bleak settings and cynical characters" , "Kind of dark film" .)