mouth-breather 

Complete dumbass that finds it difficult to even breathe.

Matt Kulow

mouth-breather by fartknocker4 August 11, 2003

mouth-breather 

Someone incapable of breathing out their nose because their mouth is always yapping. They can often be seen in forums where they're assumed to be clever. However, assumptions usually land you in jail.

Kia salespeople=everybody at Kia, involved with Kia or even knows about Kia is a mouth-breather.

mouth-breather by am_rockstar December 28, 2005

Mouth-breather 

Someone who no longer wears a mask indoors for large gatherings. These people are not anti-maskers/anti-vaxxers and used to wear their masks. Due to unclear expectations set by the CDC, state governments, businesses, and peers, they no longer wear their mask.

I was going to go to a wedding this weekend, but I'm sure there will be a lot of Mouth-breathers at the event.

Mouth-breather by wells33abducted December 16, 2021

Mouth-breather 

Matthew Best

Damn they're such a mouth-breather

Mouth-breather by spicyjfc August 27, 2022

Open Mouth Breather 

Open Mouth Breather - An individual that breathes through their mouth when not exerted. The individual appears to be, and ususally is, perpetually confused, not very bright, an idiot.

You see someone from Wisconsin driving along. As you pass them you see their profile and their mouth is wide open, an Open Mouth Breather. Although they are looking straight ahead, they don't see traffic stopping and slam their brakes on at the last moment. This is an example of an OMB (Open Mouth Breather)

Open Mouth Breather by Nicholas Esayian November 2, 2007

Open-Mouth Breather

Someone who keeps their mouth open, often with tongue sticking out; appearing mentally deficient. Implying the person has brain damage or is mentally deficient.

All his friends were idiots and morons; the biggest collection of open-mouth breathers I've ever seen.

Open-Mouth Breather by Timbotron3000 May 30, 2006

Floor Squeakin' Mouth Breather 

Phrase meaning a large woman or man that is out of breath after only a few steps. Not attractive in the least this person resembles "Jabba the Hut" with legs.

Get a load of that Floor Squeakin' mouth breather going into Old Country Buffett, you can't wash all the parts of that gal.

If that Floor squeakin' mouth breather had a red shirt on he would look like an ugly Kool-Aid. O yea!!!

Floor Squeakin' Mouth Breather by Buck Awesome August 27, 2009