tyrannical

adj

1. (not-comparable)Of, or relating to tyranny or a tyrant.
2. (comparable)Despotic, oppressive, or authoritarian.

   “a tyrannical regime”

   “tyrannical rulers”

   “She met more than a quarter of all the American presidents who have ever lived, five popes, hundreds of national leaders, from the saintly, such as Nelson Mandela, to the tyrannical, including Robert Mugabe and Nicolae Ceausescu[…]”