(idiomatic, informal) A greeting, similar to how are you?; what's happening?; what's up?; what's new?

Contraction of what is more.

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

(Ireland) What's happening?

(slang) what is happening?; what's up?

Alternative form of what's the craic

(colloquial) What do you want to drink?

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

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

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