plural of what; used as a stand-in to collectively pluralize arbitrary instances of things. Often used along with whys, hows, etc.

(euphemistic, African-American Vernacular) What the hell.

(UK, dated) Used to add emphasis to, and to seek agreement with, a previous statement.

Alternative form of what's what

(idiomatic) Precisely what the situation really is or what the facts truly are; the true state of things.

(rare) Because of, due to.

What about; used to ask someone to consider something or someone that they have apparently not considered.

For what purpose. / (colloquial) For what reason; why.

(idiomatic, colloquial, usually with "give someone") An unspecified punishment or rebuke

What is. / What has. / What does.