Number-picking casino game (4)
I believe the answer is:
keno
'number-picking casino game' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for keno that I've seen before include "A bingo-like game" , "gambling game" , "game of chance" , "2 8 [CASINO GAME]" , "gambler's choice" .)