A person who acts stupid but is really smart but only when it is needed.
Lets say Bob goes to school and steals some cafeteria food, pretty stupid. But when he takes his Algebra final he makes a 100. This would be a jawmuncher.

This word is commonly used in middle and high school when talking about a friend that does stupid things outside of school but is smart inside of school.
by Max June 17, 2006
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An idiot, or otherwise unintelligent person. A pratt.
He's a Jawmuncher
by Anthony Hawk August 27, 2008
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Person 1: Hey are you hyped for the new Dino Crisis game?
Person2: No, I'm not a jawmuncher
by ThePandorasBox August 28, 2018
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