Acronym for Post Breakup Resentment Disorder.
P.B.R.D or P-BuRD is the act of unjustly hating someone you have dated.
Typically only labelled as P-BuRD once the average period of time it takes to "Get over" someone has passed, yet feelings of Hatred and Resentment are still present.
Al "Man, Joan keeps gossiping behind my back about how much of a jerk I was to her."
Jeff "Didn't you let her keep the friends? And you quit that club you were both in so that she wouldn't have to? Plus, hasn't it been, like, over a year since you two broke up?"
Al "Yeah, I know. She's got some serious P.B.R.D."