What is Udk?
Common short way of saying, YOU DON'T KNOW!! Often followed by, "Nope, nope you don't."
Rakhi: What's up your butthole?
Aaron: Dude, idk.
Rakhi: DUDE, UDK.
Aaron: W00ts your butthole.
Rakhi: I guess
Aaron: Duh.
See idk