Greek getting behind corruption (5)
I believe the answer is:
graft
'corruption' is the definition.
(thesaurus)
'greek getting behind' is the wordplay.
'greek' becomes 'gr'.
'getting' means one lot of letters go next to another.
'behind' becomes 'aft' ('aft' can be a synonym of 'behind'**).
'gr'+'aft'='GRAFT'
(Other definitions for graft that I've seen before include "Slip" , "Transfer of tissue - hard work!" , "Make money from corruption" , "Hard work - illicit gain" , "Surgical transplant" .)