preconception
prepossession
parti pris
preconceived opinion
preconceived idea
preconceived notion

I don't have any preconceived notion of what he wants to do.

I don't have any preconceived notions about how big it should be.

My surprise was at the preconceived notion that you could not approach the "large black man."

They went with preconceived notions based on their experience and training.

He did not come to this with any preconceived notion.

"You don't ever go into a fight with any preconceived notions."

"I came in with some preconceived notions based on press reports," she said.

Or at least, her preconceived notion of what a world leader should be.

I did not hold any preconceived notions about the parties involved.

The first, without any preconceived notions, was more than 30 years ago.