A mastermind is a brilliant thinker with original ideas. You might be a chess mastermind or a criminal mastermind: either way, people will not want to oppose you.
Inventors, intellectuals, and famous geniuses call all be called masterminds, from Albert Einstein to theoretical physicist Dr. Shirley Jackson. You could also call people who are successful in their fields — especially if they come up with new ways of doing things — masterminds. Even a brilliant jewel thief might be called a safe-cracking mastermind. As a verb, to mastermind is to act as the leader of some complex plan or scheme.