ty ‧ rant /ˈtaɪərənt $ ˈtaɪr-/ BrE AmE noun [countable]
[ Date: 1200-1300 ; Language: Old French ; Origin: tyran , tyrant , from Latin tyrannus , from Greek tyrannos ]
1 . a ruler who has complete power and uses it in a cruel and unfair way:
The country had long been ruled by tyrants.
2 . someone who has power over other people, and uses it cruelly or unfairly:
My headmaster was a real tyrant.