The name of something the speaker does not want to mention, but which is known, or very likely to be known, to the listener. It can be plural (as in "... the you-know-whats").

(idiomatic) A phrase used to get someone's attention before announcing something.

Used to introduce, or alluding to, an apt adage.

Used to allude to something unsaid or hinted at.

(colloquial) You are familiar with the situation I am describing; used to establish common ground with the interlocutor

Alternative form of do you know what I'm saying

(informal) Used as a rhetorical question to confirm agreement, knowing or understanding at the end of a statement.