A phrase used to ask about something odd, or what the point of something is. The word "that" can also be replaced with whatever noun the person is asking about. It is also common to inerject the word "fuck" into the phrase to express shock or discust.
1. A casual greeting or conversation starter, somewhat of a rhetorical question.
Usually followed by something like "Not much, you?," "Nothing much," or even answered with a "Hey man, how's it going?"
syn: How's it going? What is new?
2. syn. What can i do for you?, What would you like? What's on your mind?
2. Person #1: Hey come here for a second, I have to ask you something.
Person #2: Ok, what's up?
By Rosalind
What's Up
A question that means "hi" or "What are you doing"
It can get annoying, but people don't seem to understand that.
The best way to answer is "I think it's the opposite of down" if you are annoyed by this question