shortened version of "i dunno", which is a shortend version of "i dont know", which is a shortend version of "i do not know"

When you think up something brilliantly righteous while baked.

Basically the same thing as iunno, it is a quickened version of "I do not know", used in both chatting and in informal speech.

It's history may trace back to Homer Simpson, who often makes a sound that is in between "iono" and "iunno". (Says a lot about his intelligence, doesn't it?)

12 year-old internet chatter's way of saying "I don't know."

retarded way of spelling i don't know

Slang for "I don't know"

This is the slang version of the phrase, "I don't know?"