Sorry if it's a trivial question, but when someone uses what's up as a greeting I have no idea what they want to hear. What are the possible answers and what does this question mean exactly?
Learn English – an appropriate response to “what’s up” greeting
greetingsslang
Best Answer
“What’s up?” is a greeting whose meaning is mostly irrelevant in that the asker doesn’t want an answer to the literal question which means something like “What is new?” or “What’s happening (right now/in your life)?”.
The simplest response if you don’t have information you want to share immediately with the asker is probably just to say something like “not much”, “not too much”, or “hey (man/dude)”. If you’re offered “what’s up” in response to a greeting of your own, you should read it as a request for you to proceed to the content part of what you want to talk about.