Noah Webster's New International Dictionary of the English Language

1. (v. i.) To act the tyrant; to exercise arbitrary power; to rule with unjust and oppressive severity; to exercise power others not permitted by law or required by justice, or with a severity not necessary to the ends of justice and government; as, a prince will often tyrannize over his subjects; masters sometimes tyrannize over their servants or apprentices.

2. (v. t.) To subject to arbitrary, oppressive, or tyrannical treatment; to oppress.