1. [mid-19C+] excellent, wonderful; also intensified as boss like hot sauce.
2. [mid-19C+] best; often as the boss, the best.
3. [mid-19C+] superior, important, influential.
4. [late 19C] of criminals, very dangerous.
5. [late 19C] (US) arrogant, overbearing.
6. [1960s] dedicated, obsessed with.
7. [2000s] important, meaningful.
[1960s] (US black) a thoroughly experienced, professional, worldly wise pimp who may even transcend pimping for superior occupations; the term can be applied to any admirable figure outside the pimp milieu.