Tyrant

Part of speech: noun (n.)

1. An absolute ruler; a sovereign unrestrained by law or constitution; a usurper of sovereignty.

2. Specifically, a monarch, or other ruler or master, who uses power to oppress his subjects; a person who exercises unlawful authority, or lawful authority in an unlawful manner; one who by taxation, injustice, or cruel punishment, or the demand of unreasonable services, imposes burdens and hardships on those under his control, which law and humanity do not authorize, or which the purposes of government do not require; a cruel master; an oppressor. "This false tyrant, this Nero." Chaucer. Love, to a yielding heart, is a king, but to a resisting, is a tyrant. Sir P. Sidney.

3. Any one of numerous species of American clamatorial birds belonging to the family Tyrannidæ; -- called also tyrant bird.

Part of speech: verb (v.)

To act like a tyrant; to play the tyrant; to tyrannical. [Obs.] Fuller.