A phrase to
show your acceptance and/or and or approval of an
idea or event. Or... if used in certain situations a way of expressing your discontent caused by a
person's actions, ideas, or events.
a)1: what's
good my homie?
2: not much man, just been
chillin.
1: that's what's up.
b) so you'
re gonna side with them over me, huh? That's what's up.