"Forget it!” (2,4)
'forget it' is the definition.
(both can be used to reject a request)
This is the entire clue.
(Other definitions for no dice that I've seen before include "Shan't play!" , "Refusal (to play)" , "Emphatic refusal" , "Absolutely not" , "Said to indicate failure" .)
(Another definition for no deal that I've seen is " I won't settle for that!".)
(Other definitions for noway that I've seen before include "Absolutely not!" , "Out of the question - lacks route" , "Under no circumstances!" .)