A person who dosent understand; stupid; dumb; etc
"That person is a mouth breather."
"Ugh, you're such a mouth breather."
A person who's so unbelievably dumb, they couldn't even be bothered to breathe through their nose. To put it simply, mouth breather is another word for an idiot.
"That guy, *name here* is nothing but an inconsiderate, close-minded mouth breather!"
One who doesn't know how to breathe through their damn nose, causing them to constantly pant like dogs.
"Dude, Steve is such a fucking mouth breather"
A person who without hesitation wil tell on you or someone who gossips too much and wont keep their mouth shut
You know the feds will be at your door if bob knows what you're doing, he's a 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.