Tyrant
A tyrant (from Greek τυραννοσ) is one possessing absolute governmental power. In Classical Antiquity the word tyrant did not always have inherently negative implications; it merely designated anyone who assumed power for any period of time without a legitimate basis of authority.The first to have the title of tyrant was Pisistratus in 560 BC.
In modern times tyrant has come to mean a dictator who rules with cruelty.
Bullying is a form of tyranny within a family, among schoolchildren, etc.
