1. I immediately think of the old joke, i.e. "What do you call a scouser in a suit? A: the offender." (variant: A: the accused).
2. To be more serious, then, working-class, young, single, male.
3. Legal, courts, opposite of 'straight'.
4. Mainly from TV.
Oddly, thinking about it more, many of the usual '...offender' words didn' spring to mind (no sex offenders, for example). And my immediate reactions were confined to Police Court-type scenarios.
Is that any help, and why are you asking/
Allen.