1 definition by Randall Wynn

Top Definition
1. Someone who is incapable of breathing through their nose

2. Someone stupid who is unaware that their mouth is gaping open, often taking in gallons of air and spewing their own dry, bacteria rotten maw into your clean air in your vicinity.
Never let a mouth-breather speak to you very close, or you might regret it.
by Randall Wynn April 06, 2008

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