Swindle flourished: moneylenders flee (8)
I believe the answer is:
Here is my best explanation:
'swindle' is the definition.
(flimflam is a kind of swindle)
'flourished moneylenders flee' is the subsidiary indication.
'flourished' becomes 'fl' (I've seen this in other clues).
'moneylenders' becomes 'imf' (International Monetary Fund).
'flee' becomes 'lam'.
(Other definitions for flimflam that I've seen before include "rot", "swindle", "Deception - nonsense" and "deception".)