Retaliate for Geneva’s corruption (6)
I believe the answer is:
avenge
'retaliate for' is the definition.
(to avenge is to retaliate or get revenge for)
'geneva's corruption' is the wordplay.
'corruption' is an anagram indicator.
'geneva' anagrammed gives 'AVENGE'.
(Other definitions for avenge that I've seen before include "eg Nave (anag.)" , "Requite, repay" , "Geneva (anag)" , "Exact retribution, take satisfaction for injury" , "Redress, vindicate" .)