1. literally, someone who lacks enough intelligence that they never learned to breathe through their nose.

2. a really dumb person.

a person who lays in bed next to you asking 1,000,000s of questions and even when they are not talking you still get to breathe in their out cause they are breathing through their mouths

someone who is ignorant to the social courtesies of public movement. consequently, they stifle the mobility of thinking humans by becoming an obstacle which must be negotiated. they can be identified by their despondent facial expressions and wide-open mouths .

The vile and filthy septic tank where the worst elements of the lesbian community congregate and behave like cyber cunts. Its existence benefits the rest of the lesbian community by attracting trolls, antisocial personalities and mouthbreathers, thereby segregating them from the rest of the lesbian population in a virtual holding pen.

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 ...