One of a class of men who taught eloquence, philosophy, and politics in ancient Greece; especially, one of those who, by their fallacious but plausible reasoning, puzzled inquirers after truth, weakened the faith of the people, and drew upon themselves general hatred and contempt.
- One skilled in elaborate and devious argumentation.
- A scholar or thinker.
- Any of a group of professional fifth-century B.C. Greek philosophers and teachers who speculated on theology, metaphysics, and the sciences, and who were later characterized by Plato as superficial manipulators of rhetoric and dialectic.