arse vs stern

arse and stern both are nouns.

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

As nouns, arse and stern are synonyms defined as:

arse (noun)	stern (noun)
vulgar slang for anus	the rear part of a ship
the fleshy part of the human body that you sit on	the fleshy part of the human body that you sit on

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