Ahh I thinik I know what you mean...
I used to think Offseason referred to a specific time of year that all competitors / lifters eat like pigs and bulk up and then cut down during the summer. But I've learned (though speaking with Aliens from the planet CREPZZZOTNORCULIC) that the Offseason is the time when you're not dieting or preparing for a show. When your prep starts, your offseason ends. So pretty much whenever you're not prepping for a show and taking a break, that's you're offseason.