authoritarianism vs autocracy

authoritarianism and autocracy both are nouns.

Word	Noun	Adjective	Verb	Adverb
authoritarianism	Yes	No	No	No
autocracy	Yes	No	No	No

As nouns, autocracy is a hypernym of authoritarianism; that is, autocracy is a word with a broader meaning than authoritarianism:

authoritarianism: a form of government in which the ruler is an absolute dictator (not restricted by a constitution or laws or opposition etc.)
autocracy: a political system governed by a single individual

Other hypernyms of authoritarianism include autarchy.

authoritarianism (noun)	autocracy (noun)
a form of government in which the ruler is an absolute dictator (not restricted by a constitution or laws or opposition etc.)	a political theory favoring unlimited authority by a single individual
	a political system governed by a single individual