low-lifer

A person who spends a massive amount of time doing something that wont benefit their life at all, Such as a person who plays Call of duty: Modern Warfare2, 24/7.
> John:Dude, All this month i played COD and only slept like 4 times.
> James:Dude.... Are you for real?
> John:Yeah, Man!
> James:You're a real low lifer, Bro.