1) A replacement for the word jackass 2) a inside joke that is often formed between a group of friends when they have a mutual friend named jack, especially if he's a total Jackass or he mistreats girls
1)Greg: My science teacher is a total jackbutt!
Bill: Dude that is such a sixth-grade thing to say!
2) Anne: So Jack's my friend and all but he's being a total Jackbutt! I mean he Kissed Nicolebut he doesn't even like her!!!! What a Jackbutt! No offense to Jack's butt.