is someone who digs his grave with his teeth.
someone who consumes more than they should — especially eating and drinking too much
or (the expression): "a glutton for punishment" refers to someone who persist in some activity despite negative consequences (as though loving the punishment)
or (the expression): "a glutton for whatever" refers to people who like whatever a lot — such that "a glutton for sunshine" loves sunshine.
Gluttony is an instance or a habit of eating or drinking like a glutton.
Much more rarely, glutton can reference a kind of wolverine in northern Eurasia.