a tard and a half - a complete idiot who can't do anything and makes your day wo

a complete idiot who can't do anything and makes your day worse just by being around

My uncle is a tard and a half. He tried to paint the house and ended up painting his own face.

My teacher's pet is a tard and a half. He got all the questions right and then wrote the answer in crayon.

My little brother is a tard and a half. He tried to build a fort and it collapsed on top of him.