Synonyms for Mastermind (same or very similar meaning)
WordNet sense 1 (someone who creates new things):
originator, conceiverWordNet sense 2 (someone who has exceptional intellectual ability and originality):
brain, genius, Einstein, brainiacWordNet sense 3 (plan and direct (a complex undertaking)):
direct, engineer, orchestrate, organize, organiseFrom the ODE community, based on WordNetadd/edit