Although the term originally applied to generally wise men, it was applied by Plato to various teachers of whom he disapproved, including Protagoras, Gorgias, Thrasymachus, and Hippias of Elis. Plato generally treats them as charlatans who talked purely for victory and took money for teaching the technique. In fact their general stance seems to have been not unlike that of Socrates, with a reasonably sceptical attitude to speculative cosmologies, such as those of the Eleatics, and a reasonable insistence on going to the foundations of morality and epistemology.
Philosophy dictionary. Academic. 2011.