Best definition
How are you? ( as in Hello David what’s up? ).
Also, what’s new ( with you ); what’s up; what

What’s going on, what is happening.
Gained currency from the 1940s
Bugs Bunny cartoons in which the rabbit repeatedly says “What’s up, Doc?”

Whazzuuup at the office these days?
whazzuuup: define #2
A comedy catching Phrase used often to express the shorter version of ‘What’s up’ in a crazier manner. The one says Whazzup, then the others react “WHAZZUUUP!” Used in ‘The Annoying Orange: Hey banana’ and ‘Scary Movie 1’. Used in conversations, online and on the telephone as well.
Shortay: ‘Hey man…’

Raay: ‘Whazzuuup!

Shortay: ‘Whazzuuuuuuuup!’

Cinday: ‘Whazzuuuuuuuuup!’

Dwayt: ‘Whazzuuuuuuup!’

Brendha: ‘Whazzuuuuuuuup!