Definitions

1. noun

an expression used to indicate that one is uncertain or unaware of the answer to a question

“I said ‘dunno’ and quickly changed the subject.”

2. verb

to express uncertainty or ignorance about something

“He just shrugged and said he dunno the answer to the trivia question.”

3. interjection

used to express uncertainty or ignorance about something

“Dunno, but I’m going to try to find out!”