ty·ran·ni·cal 
(tĭ-rănĭ-kəl, tī-) also ty·ran·nic (-rănĭk)
(tĭ-rănĭ-kəl, tī-) also ty·ran·nic (-rănĭk)adj.
1. Of or relating to a tyrant or tyranny: a tyrannical government.
2. Characteristic of a tyrant or tyranny; despotic and oppressive: a tyrannical supervisor. See Synonyms at dictatorial.
ty·ranni·cal·ly adv.
ty·ranni·cal·ness n.