ten·der·loin 
(tĕndər-loin′)
(tĕndər-loin′)n.
1. The tenderest part of a loin of beef, pork, or similar cut of meat.
2. A city district notorious for vice and graft.
[Sense 2, after the Tenderloin, an area of New York City (from the easy income it once afforded corrupt policemen).]