dunce cap
dunce's cap
fool's cap

He gave her a look that suggested she might want to be measured for a dunce cap.

The basket was a dunce cap designed to prevent prisoners from seeing one another.

I wondered if they made dunce caps big enough to hide under.

Any candidate who looks too comfortable in a dunce cap has a real problem today.

The other was a small boy wearing a dunce cap.

It sat on top of his small head like a dunce cap.

Johnny Cat just doesn't have it, so the professor forces him to wear the dunce cap.

One online Army discussion group elicited an attack on the dunce cap.

The red cone sat on his head like a dunce cap.

Their hairless skull looked as if they had put on a dunce cap.