Used to describe someone who is in the habit of finding ways to avoid doing their job. They tend to use such tactics as extended bathroom breaks, pretending to be deep in thought reading something while they are actually texting on their phone or taking extended lunches. The name is derived from the Wilford Brimley malaprop "diabeetis" since the folks this term apply to tend to be moribdly obese as well as morbidly lazy.
Did you see Mitch beetising off again? It sounded like the fuckin' NYC Fourth of July fireworks finale in the bathroom but that was over a half hour ago. I suppose it is pretty useless, though. Even if he were here, he'd be hunched over his desk IM'ing his boy toy all day and yelling at everyone who asked him for help.