Dishonest scheme of rascal cut short (4)
I believe the answer is:
scam
'dishonest scheme' is the definition.
(I've seen this before)
'rascal cut short' is the wordplay.
'rascal' becomes 'scamp' ('scamp' can be a synonym of 'rascal').
'cut short' means to remove the last letter.
'scamp' with its last letter taken away is 'SCAM'.
'of' is the link.
(Other definitions for scam that I've seen before include "Fraud, trick (slang)" , "Swindle, fraud (colloq.)" , "Fraud, dishonest scheme" , "rook" , "Dubious operation" .)