Get even for (6)
I believe the answer is:
avenge
'get even for' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for avenge that I've seen before include "Get back at for (a wrong)" , "Inflict retribution" , "Get one's own back for" , "Carry out retribution" , "Geneva (anag)" .)