Roulette color (4)
I believe the answer is:
noir
'roulette color' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for noir that I've seen before include "Film featuring bleak settings and cynical characters" , "type of film" , "Dark in France, like brooding films of 40s and 50s" , "Kind of dark film" , "film genre" .)