Tyrant

A tyrant (Greek τύραννος, tyrannos), in its modern English usage, is a ruler of a horrible and oppressive character who is an absolute ruler unrestrained by law or constitution, and/or one who has usurped legitimate sovereignty. A tyrant usually controls almost everything. The original Greek term, however, merely meant an authoritarian sovereign without reference to character, bearing no pejorative connotation during the Archaic and early Classical periods, though it was clearly a bad word to Plato, and on account of the decisive influence of political philosophy its negative connotations only increased down into the Hellenistic period.