1. An sort of pun created from another racist name for black people: "spook".
2. An abbreviation of another racist term for blacks: "jig-a-boo".
Racist #2: "Yeah, that spook had lips so big his head tipped forward".
Racist #1: Yeah, it was as long as a mule's lip from his ear down!"
Racist #2: "He was dark, too!"
Racist #1: "No kidding! That boo was so black he was almost purple!"
Now meaning girl or boyfriend