Fool with money coming back to get organ (6)
I believe the answer is:
kidney
'organ' is the definition.
(kidney is a kind of organ)
'fool with money coming back' is the wordplay.
'fool with' becomes 'kid' (kidding is a kind of fooling. I am not sure about the 'with' bit.**).
'money' becomes 'yen' (Japanese currency).
'coming back' says the letters should be written backwards.
'yen' reversed gives 'ney'.
'kid'+'ney'='KIDNEY'
'to get' acts as a link.
(Other definitions for kidney that I've seen before include "Sort" , "body part" , "nature" , "temperament" , "Glandular organ that removes waste matter from blood" .)