Someone who disagrees with something that is widely accepted by others, seemingly for no reason. The word comes from toothpaste advertisements, which often claim that "Nine out of ten dentists" recommend using their brand of toothpaste.
Mark: "I was making plans with the boys, but Adam kept arguing about all of our plans even though everyone else was on board."
Craig: "Man, the tenth dentist really had to go and ruin the fun for everyone, huh?"
Craig: "Man, the tenth dentist really had to go and ruin the fun for everyone, huh?"
by dKoschei August 15, 2019