Dumb Donut
Someone who isn't the brightest. One could even say they have a gap between their ears. They are essentially the opposite of a smart cookie.
Carol: My sister is pregnant and I can't wait for the gender reveal. It's so exciting to find out if I'm going to be an aunt or uncle.
Carl: Oh Carol, you are a dumb donut!
Carl: Oh Carol, you are a dumb donut!
dumb donut
a slut who cheats. See "Spare me the Details" by The Offspring.
She's a dumb donut, I can't believe she dit that behind your back.