The incorrect spelling of "Billie Jean", a 1983 hit song by Michael Jackson.

Billy Jean - derrog. n. A permiscuous girl that has gone back to each lover and claimed that each one got her pregnant hoping someone will step up and own the responsibility.

Also, a girl who gets pregnant to keep a man. Coined from the hit single from Michael Jackson called "Billy Jean" which was about an actual case where a fan claimed Michael got her pregnant and was trying to sue for money.