(idiomatic) Or something else; allows for the existence of an unexpressed alternative to what was said.

Alternative form of know what is what

(idiomatic) To be experienced or well-informed. / (idiomatic) To be astute, perceptive enough to observe a situation that is not what it seems and recognize its true nature.

plural of whatness

(philosophy) Essence; quiddity. / Quality; quantity.

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

(defensively) Why are you asking? Why do you want to know?. / Mind your own business; it's none of your business.

(idiomatic, colloquial) What did you say?; Huh?; expresses incredulity.

(informal) An informal greeting.

(African-American Vernacular) What's up? What's going on?