1. To headbutt someone.
2. To prepare to or attempt to headbutt someone.
3. One who frequently engages in headbutting
(acceptable as either lower or upper case)
"He just pulled a rupkey on that guy"
"Looks like Winkler just got rupkied"
Person 1: Man, he fights dirty, he just keeps headbutting people.
Person 2: Yeah, he's such a Rupkey