1. A person who is not actually fat, but who acts fat. Often a skinny person is referred to as a "chubster" after they have displayed their extensive laziness.
Person 1 "Hey could you get me a beer?"
Person 2 "Im to busy eating out of the fridge to get your a beer"
Person 1 "Your such a such a chubster, you weigh 110 and you eat more than a fat guy"