stern vs arse

stern and arse both are nouns.

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

As nouns, stern and arse are synonyms defined as:

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

stern (adjective)	arse (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