tyranny vs tyrannical

tyranny is a noun but tyrannical is not a noun.

Word	Noun	Adjective	Verb	Adverb
tyranny	Yes	No	No	No
tyrannical	No	Yes	No	No

tyranny (noun)	tyrannical (noun)
a form of government in which the ruler is an absolute dictator (not restricted by a constitution or laws or opposition etc.)
dominance through threat of punishment and violence

tyranny (adjective)	tyrannical (adjective)
	marked by unjust severity or arbitrary behavior
	characteristic of an absolute ruler or absolute rule; having absolute sovereignty