you know what?

1 of 2

idiom

informal

1

—used to emphasize the statement that comes after it

You know what? I never trusted her.

She lied to me again, but you know what? I really just don't care anymore.

2

—used to get someone's attention

Hey, you know what? I'm hungry.

you-know-what

2 of 2

noun

informal

1

—used in speech to refer to something that is not named but is known to both the hearer and speaker

I've hidden the you-know-what in the closet.

2

—used in place of a rude or offensive word in order to express anger or annoyance

He's a complete you-know-what.