OPJ is also a slang term used by many Veronica Mars fans. It refers to one of the characters, Logan Echolls, who is coined the name Obligatory Psychotic Jackass in the very first episode of the show.
"And let's not forget Logan Echolls. His dad makes twenty million a picture. You probably own his action figure. Every school has an obligatory psychotic jackass (OPJ). He's ours."
by kissthelibrarian October 17, 2007