austere vs stern

austere is not a noun while stern is a noun.

Word	Noun	Adjective	Verb	Adverb
austere	No	Yes	No	No
stern	Yes	Yes	No	No

As adjectives, austere and stern are synonyms defined as:

austere and stern: of a stern or strict bearing or demeanor; forbidding in aspect

As adjectives, austere and stern are synonyms defined as:

Other synonyms of austere include severe, stark.

austere (noun)	stern (noun)
	the rear part of a ship
	the fleshy part of the human body that you sit on

austere (adjective)	stern (adjective)
practicing great self-denial	severe and unremitting in making demands
of a stern or strict bearing or demeanor; forbidding in aspect	not to be placated or appeased or moved by entreaty
severely simple	of a stern or strict bearing or demeanor; forbidding in aspect
	severely simple