What’s up?

what's up

1. What's going on? What's happening? So, what's up with Terry? He seems off lately. Well, what's up? Why are you so upset with me?
2. How are you? How are things? (Used as a greeting that doesn't require an answer.) Hey, Tom, what's up? Long time no see! A: "Hi Sarah!" B: "What's up, Janet!"
See also: up
Farlex Dictionary of Idioms.

What’s up?

interrog. What is going on?; What is happening? (see also (T)sup?, Wusup?.) Haven’t seen you in a month of Sundays. What’s up?
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • what's up
  • What's up?
  • what's cooking
  • What's cooking?
  • What's going on?
  • What’s going on?
  • What's with (someone)?
  • what's with somebody?
  • What's up with (someone)?
  • What’s happening?