potentate

noun

1. A powerful leader; a monarch; a ruler.

   “But Kings and mightieſt Potentates muſt die, For that's the end of humane miſerie.”

   “She was now one of a group of oriental beauties who, in the second act of the comic opera, were paraded by the vizier before the new potentate as the treasures of his harem.”

   “Life for ordinary barons in Outremer Jerusalem was probably better than for kings in Europe, where even potentates wore unlaundered wool and lived in bare-stone draughty keeps with rough furniture.”

   “Anyone expecting such a speech has forgotten that Trump’s first impulse is to please. He is constitutionally incapable of displeasing a live audience, let alone a foreign potentate who has recently lassoed him with a golden chain.”

   “Bad news for a certain kind of pedantic patriot (look away now, Jacob Rees-Mogg). Prince Charles has debased the English language – and in a letter to a foreign potentate, no less.”

2. A powerful polity or institution.
3. (derogatory)A self-important person.
4. (humorous)Someone acting in an important role.

   “"Those foreigners," thought the female potentate of the Sun, "won't know what to order; but I'll show them what a good supper is."”

adj

1. (obsolete)Regnant, powerful, dominant.