When a boy/girl wants to know how you feel about them.

MY dad says wassup to his mom every night on the phone and "Wassup" is not an actual word until NOW!!!

What's up shortened because people are too lazy to speak correctly.

The VERY offensive swear word

Get up off that seat, or else.

wassup
/ˈwɒsʌp/
used as a friendly or informal greeting.
also used when boys say it to other boys(mostly)

A word. A very amazing word that everyone should use every day. But, sadly not everyone does. :(