Offender (7)
I believe the answer is:
culprit
'offender' is the definition.
(I know that culprit is a type of offender)
This is the entire clue.
(Other definitions for culprit that I've seen before include "Offender or guilty party" , "One perpetrating crime" , "baddie" , "Perpetrator of a wrongdoing" , "The person to blame, the guilty one" .)