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2.
A Blond whose a really fat bitch who thinks she's popular. She could be a cheerleader so be alert. You know it's a McFattie when you see a hint of crust on her chin.Just be alert also because she can and will crush you.She can be notified as Tara M.
Run! The McFattie is coming......,"My fucking legs! she broke my fucking legs! Man that's one big piece of shit!"
by Keira Huntly July 12, 2006
 
1.
Someone who eats too much McDonald's
That guy has been eating McDonald's all this week. He's starting to become a McFattie.
by RickrollingIsOverrated July 05, 2009