A person (usually a man) that acts so stupid you just wanna strangle them. They screw things up, say stupid stuff, and have nothing intelligent to say. Their voice is usually that of one Napoleon Dynamite.
Moron Man: "hey, man, got any weeeeed? ha.. ha.. ha"
Tanya: "Hey, man, you're a fuckernut! You're the biggest piece of trash I ever laid eyes on."
Similar to a fluffernutter, but made during sex with peanut butter and semen and fed to the woman.
I blew my load onto the bread, spread some peanut butter on the other slice, put them together and stuffed it in her mouth. She loved that fuckernutter.
Fuckernut is used when you do something that causes great pain to your body. I first used this word when I stubbed my pinky toe on a doorframe. You can also call someone a fuckernut. It can mean "Fucking retard". Nut meaning crazy person.