sovereign vs autonomous

sovereign is a noun but autonomous is not a noun.

Word	Noun	Adjective	Verb	Adverb
sovereign	Yes	Yes	No	No
autonomous	No	Yes	No	No

As adjectives, sovereign and autonomous are synonyms defined as:

sovereign and autonomous: (of political bodies) not controlled by outside forces

Other synonyms of sovereign include independent, self-governing.

sovereign (noun)	autonomous (noun)
a nation's ruler or head of state usually by hereditary right

sovereign (adjective)	autonomous (adjective)
greatest in status or authority or power	(of political bodies) not controlled by outside forces
(of political bodies) not controlled by outside forces	(of persons) free from external control and constraint in e.g. action and judgment
	existing as an independent entity