Criminal file that's wrong put right (5)
I believe the answer is:
lifer
'criminal' is the definition.
(prisoner serving a life sentence)
'file that's wrong put right' is the wordplay.
'that's wrong' indicates anagramming the letters.
'put right' becomes 'r' (I've seen this in other clues).
'file' anagrammed gives 'life'.
'life'+'r'='LIFER'
(Other definitions for lifer that I've seen before include "One with very long sentence" , "person given sizeable bird" , "Rifle (anag.)" , "One given lots of porridge" , "Person serving long sentence" .)