An abbreviation for I(nsane) M(ad) B(itch). A nut job lady who is out to get someone for whatever reasons whether it'd be deep hatred or lust. Not to be confused with IBM, or I(nter-continental) B(allistic) M(issile). Ranges from Categories 1-5, 1 being within normality crazy and 5 being borderline illegal activity crazy.
Person A: Shit dude, I got an IMB after me
Person B: What category?
Person A: Like a 4
Person B: Damn. Aight I'll cover for you
Person A: Thanks B