Former prisoner (2-3)
I believe the answer is:
ex-con
'former prisoner' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for ex-con that I've seen before include "Former prisoner, in short" , "She used to serve porridge" , "Old lag" , "Person once inside, now outside" , "having defected from Tory party?" .)