despotic

[Gr. despotiko`s: cf. F. despotique.]
Having the character of, or pertaining to, a despot; absolute in power; possessing and abusing unlimited power; evincing despotism; tyrannical; arbitrary. -- Des·pot·ic·al·ly, adv. -- Des·pot·ic·al·ness, n.

adjective

1. Having and exercising complete political power and control: absolute, absolutistic, arbitrary, autarchic, autarchical, autocratic, autocratical, dictatorial, monocratic, totalitarian, tyrannic, tyrannical, tyrannous. See over/under, politics.
2. Characterized by or favoring absolute obedience to authority: authoritarian, autocratic, dictatorial, totalitarian, tyrannic, tyrannical. See over/under.

Definition: autocratic, tyrannical
Antonyms: accountable, democratic

The adjective has 3 meanings:

Meaning #1: belonging to or having the characteristics of a despot
  Synonym: despotical
  Pertains to noun: despot (meaning #1)

Meaning #2: ruled by or characteristic of a despot

Meaning #3: characteristic of an absolute ruler or absolute rule; having absolute sovereignty
  Synonyms: authoritarian, autocratic, dictatorial, tyrannical