The quality of not being there; absence.

Indicates that an area should not be entered, e.g. a military installation, or as a sign on a hotel room door.

A home is not merely a building but requires inhabitants and a friendly atmosphere.

Used to indicate that somebody does not wish to be disturbed, e.g. a sign on a hotel room door, or a "busy" mode of an instant messenger.

(Internet slang) Used to indicate that the speaker does not like something they have seen or heard.

plural of not-for-profit

(idiomatic) This may be surprising, but it's true.

(informal) Very little space (available) (of a very small room).

(colloquial) It's none of my business; indicates that one is not responsible for controlling or changing a volatile or delicate situation.

Not the first time one has been in a particular situation; used to indicate past experience.