autocrat

 
Pronunciation: /ˈɔːtəkrat/

noun

  • a ruler who has absolute power: like many autocrats, Franco found the exercise of absolute power addictive
  • an imperious person who insists on complete obedience from others: Eva was an autocrat—people didn’t argue unless they had a lot of courage

Origin:

early 19th century: from French autocrate, from Greek autokratēs, from autos 'self' + kratos 'power'