The Greek Tyrannis is often fitting:

https://en.wikipedia.org/wiki/Tyrant

> A tyrant (from Ancient Greek τύραννος (túrannos) 'absolute ruler'), in the modern English usage of the word, is an absolute ruler who is unrestrained by law, or one who has usurped a legitimate ruler's sovereignty. Often portrayed as cruel, tyrants may defend their positions by resorting to repressive means.[1][2] The original Greek term meant an absolute sovereign who came to power without constitutional right