A person who responds `I don't know' in a public opinion poll(noun)
WordNet. Princeton University. 2010.
Use "don't-know" in a sentence
"Maybe, but that would explain the don't-know category, not the he's-a-Muslim category."
"Was this a cop-out or was she practicing what Buddhists call the "don't-know mind" - that there are things we can never understand, that make sense only when we stop trying to make sense of them?"
"The Guardian, on the other hand, today cited “Labour strategists” who believe that the referendum can be won, claiming that almost half of the 50% declared no voters their estimate are persuadable, as are the 30% in the don't-know camp."