Dishonest scheme — uproar! (6)
I believe the answer is:
racket
I believe this clue is a double definition.
'dishonest scheme' is the first definition.
(type of extortion, as in a protection racket)
'uproar' is the second definition.
(I've seen this before)
(Other definitions for racket that I've seen before include "Dodgy business" , "Din of the fraudulent moneymaking activity" , "Unpleasant din" , "See 1" , "Fraudulent scheme" .)