A person who breathes through their mouth, thus having their mouth hang open. Their mouth can be anywhere from barely open, to gaping, and usually the more open it is, the more idiotic, and unintelligent they look. Mouth Breathers may or may not be intelligent, however, due to the fact that they don't realize their mouth is gaping, they just look like a moron, who may drool at any moment, but is deffinately sucking in as much air as possible.

Mouth breathers tend to be people who are bored, zoning out, very focused on something, someone with huge lips, or someone who isn't smart enough to realize their mouth is hanging open, catching flys. All tend to appear as the latter.

People who are sick and can't actually breathe through their noses do not count.
Katie: "I was sitting in class, and I looked over at Fred, who was staring dead eyed at the board with his mouth hanging open, like an idiot"

Rachel: "Ew, what a Mouth Breather"
by JelloLove September 15, 2010

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

The Urban Dictionary Mug

Your favorite word on a white mug.

Create a mug

The Urban Dictionary Mug

One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.

Buy the mug

The Urban Dictionary T-Shirt

Soft and offensive. Just like you.

Buy the t-shirt

The Urban Dictionary T-Shirt

Smooth, soft, slim fit American Apparel shirt. Custom printed. 100% fine jersey cotton, except for heather grey (90% cotton).

Buy the t-shirt
Adj: - derogative term - Someone of a lower (or no) class – Usually found in large packs in city centres – can be of any age (although motherhood stats at 14) – standard attire – Tracksuit bottoms – fake Burberry caps – jewellery from Elisabeth Duke of Argos. Derived from the fact they breathe through there mouths.
1; the mouth breathers stood in the dole queue.
2; the mouth breathers considered Primark to be an expensive shop.
3; the mouth breathers were unfamiliar with the concept of books or chewing with ones mouth closed.
by Andy The Great July 21, 2003

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

The Urban Dictionary Mug

Your favorite word on a white mug.

Create a mug

The Urban Dictionary Mug

One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.

Buy the mug

The Urban Dictionary T-Shirt

Soft and offensive. Just like you.

Buy the t-shirt

The Urban Dictionary T-Shirt

Smooth, soft, slim fit American Apparel shirt. Custom printed. 100% fine jersey cotton, except for heather grey (90% cotton).

Buy the t-shirt
1) Person incapable of their own thought, who when faced with a decision, or when asked about personal opinion on something opens up her or his mouth in shock and astonishment that there is such thing as personal opinion. With mouthbreathers it happens constantly due to damage caused by upbringing by helicopter parents, or other emotionally damaging authoritarian or social influences. Can be spotted at every step of social and economic status ladders.

2) A reason why normal people invented law of the land ( equivalent of pinning a note that states "anyone who will touch my coffee cup will get their car keyed" ) and lawyers to herd those idiots away from harming normal families.

3) Equivalent to an alarmist or a zombie - AVOID AT ALL COST - prolonged exposure might lead to compromise of inner emotional barriers and contamination of own soul with emotional AIDS. If you really want to help such person you can only put some objects in their way in hope it will trigger aha moment in them, so they will start slowly doing stuff for themselves - pretty much the same deal as when handling alcoholics. When engaging personally with help there is high chance of them making their mess your business, continuing their crazy of not doing anything for themselves.

4) Private Pyle from Full Metal Jacket after emotional fuckery by Gunnery Sgt Hartman
me (at university): So mr advisor, is what I wrote in thesis valid and does it have your okay stamp?
advisor: No, you gotta change thingie A to B
me: umm... but why? the whole world is doing A. B is kinda retarded way (provided metric shit ton of references)
advisor: No, you gotta change A to B
me: (oh fuck... im dealing with a mouthbreather here...) okaaaay, so can i post that on my blog so the whole world will know you are in favor of B?
advisor: (says nothing)
me: so, can I now assume that A stays and all is kosher?
advisor: *okay*
me: THANK YOU! (sigh... finally)

(true story)
by Spaceship Earth Astronaut November 16, 2012

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

The Urban Dictionary Mug

Your favorite word on a white mug.

Create a mug

The Urban Dictionary Mug

One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.

Buy the mug

The Urban Dictionary T-Shirt

Soft and offensive. Just like you.

Buy the t-shirt

The Urban Dictionary T-Shirt

Smooth, soft, slim fit American Apparel shirt. Custom printed. 100% fine jersey cotton, except for heather grey (90% cotton).

Buy the t-shirt
A person of low intellect who is incapable of critical thinking. A mouthbreather watches Fox News religiously and believes everything they hear there as well as anything on the Internet that validates their ignorance.
Donald Trump appeals to every mouthbreather in the country because he is as ignorant and unimaginative as they are.
by SheckyGrl January 17, 2016

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

The Urban Dictionary Mug

Your favorite word on a white mug.

Create a mug

The Urban Dictionary Mug

One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.

Buy the mug

The Urban Dictionary T-Shirt

Soft and offensive. Just like you.

Buy the t-shirt

The Urban Dictionary T-Shirt

Smooth, soft, slim fit American Apparel shirt. Custom printed. 100% fine jersey cotton, except for heather grey (90% cotton).

Buy the t-shirt
A person of inferior intellect that lacks the faculties to recognize he is breathing heavily through his drooping open mouth; one who watches Fox News and Nascar with religious zeal.
Donnie shops at Evil-Mart like all the other mouth breathers.
by Joe Flood September 04, 2007

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

The Urban Dictionary Mug

Your favorite word on a white mug.

Create a mug

The Urban Dictionary Mug

One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.

Buy the mug

The Urban Dictionary T-Shirt

Soft and offensive. Just like you.

Buy the t-shirt

The Urban Dictionary T-Shirt

Smooth, soft, slim fit American Apparel shirt. Custom printed. 100% fine jersey cotton, except for heather grey (90% cotton).

Buy the t-shirt
The only thing these crude, rude, and obnoxious people have in common with the human species is that they have a hole in their head with which they breath; otherwise, they are pretty much amoebas with vocal chords.
check your local pool hall in any small southern town
by lee ann hansen January 06, 2004

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

The Urban Dictionary Mug

Your favorite word on a white mug.

Create a mug

The Urban Dictionary Mug

One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.

Buy the mug

The Urban Dictionary T-Shirt

Soft and offensive. Just like you.

Buy the t-shirt

The Urban Dictionary T-Shirt

Smooth, soft, slim fit American Apparel shirt. Custom printed. 100% fine jersey cotton, except for heather grey (90% cotton).

Buy the t-shirt
Any human being that breathes in and out through their mouths, often engaging in idiotic and useless activity. An affinity for sexually crude humour generally accompanies.
Most of the people posting definitions here are mouth-breathers.
by Mhuur November 25, 2002

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

The Urban Dictionary Mug

Your favorite word on a white mug.

Create a mug

The Urban Dictionary Mug

One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.

Buy the mug

The Urban Dictionary T-Shirt

Soft and offensive. Just like you.

Buy the t-shirt

The Urban Dictionary T-Shirt

Smooth, soft, slim fit American Apparel shirt. Custom printed. 100% fine jersey cotton, except for heather grey (90% cotton).

Buy the t-shirt
A mechanical engineer who is much inferior to their counterpart the electrical engineer. Often found staring at a machine with mouth agape breathing through their mouth in a stupid manner and blank expression on their face wondering why the machine will not work. Luckily an electrical engineer is never far away to save the day for the mouth breather.
Hey Joe check out the mouth breather staring at the labeler like an idiot. Do you think I should go help him out?
by CitadelBulldog96 December 11, 2009

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

The Urban Dictionary Mug

Lotsa space for your liquids.

Buy the mug

The Urban Dictionary Mug

Your favorite word on a white mug.

Create a mug

The Urban Dictionary Mug

One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.

Buy the mug

The Urban Dictionary T-Shirt

Soft and offensive. Just like you.

Buy the t-shirt

The Urban Dictionary T-Shirt

Smooth, soft, slim fit American Apparel shirt. Custom printed. 100% fine jersey cotton, except for heather grey (90% cotton).

Buy the t-shirt