look up any word, like blumpkin:
 
1.
-When a loved one, friend or co-worker is excessively eating large portions of food in a short amount of time.
Karen- *eating doughnut after doughnut*

Steve- "whoa karen, you're going fat shit crazy on those doughnuts, you think you could slow down? save me a jelly filled while your at it."

Karen- "Sorry I've been a real chunker lately"
by WHOISTHISDUDE July 30, 2011
 
2.
The senseless way in which an obese person loses their temper and retaliates against tormentors.
It's an urban legend that Natalie from The Facts of Life went fatshit crazy on her skinny castmates and bit them when she heard them making fun of her huge ass.
by NuttyByNature2 July 24, 2010