A "Svengali" refers to a person who manipulates or controls another individual, often for their own benefit. The term originates from the character Svengali in George du Maurier's 1894 novel, "Trilby." In the story, Svengali is a charismatic musician who uses his influence to dominate a young singer, ultimately leading her to fame but also to her downfall. In modern usage, the term is often applied to describe someone who exerts undue influence over another, particularly in relationships or professional settings. A Svengali figure may exploit vulnerabilities, using charm or coercion to achieve their goals, making the term synonymous with manipulation and control.