1. [adj]  characteristic of an absolute ruler or absolute rule; having absolute sovereignty; "an authoritarian regime"; "autocratic government"; "despotic rulers"; "a dictatorial rule that lasted for the duration of the war"; "a tyrannical government"
2. [adj]  marked by unjust severity or arbitrary behavior; "the oppressive government"; "oppressive laws"; "a tyrannical parent"; "tyrannous disregard of human rights"
3. [adj]  of or relating to or associated with or resembling a dictatorship; "tyrannical suppression of liberty"

TYRANNICAL is a 10 letter word that starts with T.