a slang word for the word "nothing". It became popular with the movie "Big Lebowski". There is a scene in the movie where Jeff Bridges' character is the victim of a break in by some self described nihilists who proclaim they believe in nothing but because of their German accents they pronounce the word as nussing.
from the Big Lebowski - "We believe in nussing, Lebowski"
slang for the word "done". Used when you have completed or quitting a task. It is also used to describe when you are bored. Nihilists often use this word. It is popular when using this word to spell it out.
Andy quit his job today, he is dun with it.
I'm D U N (dun is spelled out).
Billy Bob was dun after a night of partying.