US uncle gets around Charlie’s fraudulent scheme (4)
I believe the answer is:
scam
'fraudulent scheme' is the definition.
(I've seen this in another clue)
'us uncle gets around charlie's' is the wordplay.
'us uncle' becomes 's am' (I've seen this before).
'gets around' means one lot of letters goes inside another.
'charlie' becomes 'C' (phonetic alphabet: alpha, bravo, charlie etc.).
'sam' placed around 'c' is 'SCAM'.
(Other definitions for scam that I've seen before include "Rip off" , "Fraudulent business scheme" , "Dubious operation" , "Hoax" , "Rip-off" .)