Or if you do something stupid, like throw a hammer up in the air and try to hit your head.
(after purposely tripping yourself) DURP!
What is up? -> What's up? -> Wassup? -> Waddup? -> Sup? -> Durp?
Guy 2: DURP!!
2) Guy 1: Lord of the Rings is epic
Guy 2: Durp.
3) Guy 1: Just completed Angry Birds and got 3 stars on every level, DURP?!
Related words: derp, durpadurp.
Synonyms: stupid, dopey, naive, clueless, clumsy, klutz, awkward, innocent, god's child.
Antonyms: aggressive, sharp, smart, brilliant, clever.