(idiomatic) What is the purpose or advantage of

(slang) Used other than figuratively or idiomatically: see that's, what's up. / (slang) Used to express acquiescence or concurrence; true; indeed.

(slang) What’s going on with you? (as a greeting)

(slang) What’s going on with you?

(colloquial, often with a following present participle or infinitive expression) Used to indicate that a specified or implied action cannot succeed or offers no advantage if successful

(slang) what's happening?; what's up? (a greeting)

(idiomatic) What is wrong with...? What is the problem with... (somebody)? Inquired regarding somebody who seems upset, worried, angry, etc.

(colloquial) What do you want to drink?

(colloquial) What is good, especially in reference to food. / (slang) What's up? a casual greeting

(Ireland) What's happening?