mouth-breather(redirected from a mouthbreather)
Someone who is dimwitted, foolish, or stupid; someone of low or stunted intelligence. Used as an insult. That bully is a such a mouth breather, I bet he has the IQ of a rock.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
n. a stupid-acting person. I always end up with a mouth-breather on a blind date.
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.