jackhelmet
A person so clueless they think a jackass is a type of cereal and a jimmyhat is a fancy hat for cats.
My neighbor is a jackhelmet. He tried to fix the Wi-Fi with a spoon and a prayer.
My friend is a jackhelmet. He told his crush he was a pizza delivery man and got rejected.
My mom is a jackhelmet. She thinks the Earth is flat and that the moon is just a giant disco ball.