TYRANT

noun

1. A usurper; one who gains power and rules extralegally, distinguished from kings elevated by election or succession.
2. Any monarch or governor.
3. A despot; a ruler who governs unjustly, cruelly, or harshly.

verb

1. To act like a tyrant; to be tyrannical.
2. To tyrannize.

adjective

1. Tyrannical, tyrannous; like, characteristic of, or in the manner of a tyrant.