DUNCE

[noun] [C] [disapproving] - a person who is slow to learn or stupid, esp. at schoolHe was such a dunce in school but now he's very successful in banking.I'm afraid I'm a bit of a dunce at arithmetic.A dunce's cap (US usually dunce cap) is a tall paper hat with a pointed end that in the past a child who had made many mistakes in their work had to wear in school.