dictatorial vs authoritarian

dictatorial is not a noun while authoritarian is a noun.

Word	Noun	Adjective	Verb	Adverb
dictatorial	No	Yes	No	No
authoritarian	Yes	Yes	No	No

As adjectives, dictatorial and authoritarian are synonyms defined as:

Other synonyms of dictatorial include overbearing.

As adjectives, dictatorial and authoritarian are synonyms defined as:

dictatorial and authoritarian: characteristic of an absolute ruler or absolute rule; having absolute sovereignty

Other synonyms of dictatorial include autocratic, despotic, tyrannic, tyrannical.

dictatorial (noun)	authoritarian (noun)
	a person who behaves in a tyrannical manner

dictatorial (adjective)	authoritarian (adjective)
of or characteristic of a dictator	expecting unquestioning obedience
expecting unquestioning obedience	characteristic of an absolute ruler or absolute rule; having absolute sovereignty
characteristic of an absolute ruler or absolute rule; having absolute sovereignty