Derived from Jerky boys charachter and adopted by many hardcore fans.
"You look like a freakin' buttnutt riding your bike in those yellow spandex biker shorts!"
2. (N) Person obsessed with butts: "Butt Fetish"
-"He just took a dump and probably has a butt nutt"
2. "Why is Pedro a Butt Nut?"
-"He is from Brazil, they like butts more than breats there."