Demi is a very attractive, muscular man. Usually with a big penis, and a big personality. Usually has a mullet, and a line of bitches waiting for him. Don't mess around with a Demi, or you'll be fucked, literally.
Dude 1: "Look how many chicks are lining up behind that dude with a mullet"
Dude 2: "Man, he must be a Demi"
Dude 2: "Man, he must be a Demi"
by Penny_Maker January 08, 2012