Sven ‧ ga ‧ li /svenˈɡɑːli/ BrE AmE noun [countable]
[ Date: 1900-2000 ; Origin: Svengali , character who uses hypnotism to get control over people in the book Trilby (1894) by George Du Maurier ]
a man who has the power to control people’s minds and make them do bad or immoral things