Fraudulent scheme (6)
'fraudulent scheme' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for racket that I've seen before include "Swindle - uncovered in the courts" , "Loud unpleasant noise" , "Din of the fraudulent moneymaking activity" , "See 1" , "Din - tennis bat" .)
(Other definitions for bubble that I've seen before include "Thin ball of liquid enclosing air or gas" , "Globule full of gas" , "Glass or plastic dome" , "Effervesce" , "See 13" .)
'fraudulent scheme' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for scam that I've seen before include "Racket" , "ploy" , "Swindle, fraud (colloq.)" , "Dubious operation" , "An informal swindle" .)