Boi

Originating from the 80's, the word "boi" came from male prison slang.

"Boi" means in prison that you are owned by someone else, and therefore, off limits. Unless you wanted to confront the owner of said "boi" about assuming ownership.

After a dominant male, Terry, makes a submissive male, Phil, his bitch, the prison population would refer to this submissive male as 'Terry's boi.'

Tyrell: Damn son, look at that new blood. Wouldn't mind stabbin' his guts in the shower.
Dante: Mmmmhmm. I wouldn't though, that's Terry's boi, less you wanna fuck wit Terry. My dude picked him off quick.
Tyrell: Fuck man, why I always gotta fuck that wore out bitch Lucas? He used to appreciate what I give him now he makin it feel gross, like rape or some shit.
Dante: Leave me out of that shit mayn, that's your boi. Fuck out of here.