- Eye dialect spelling of do not know; eye dialect spelling of does not know.
- I dunno the answers to any of those questions, and you dunno and he dunno either.
- "Where'd he go?" / "Dunno."
Usage notes 
This is one of the only verb forms in English that regularly does not require a pronoun. When the pronoun is not given, it is assumed to be I; all other pronouns must be given. It is never mandatory to drop I, although it is most common to do so when dunno is the only word in the sentence.
dunno (plural dunnos)