arse vs tail end

arse and tail end both are nouns.

Word	Noun	Adjective	Verb	Adverb
arse	Yes	No	No	No
tail end	Yes	No	No	No

As nouns, arse and tail end are synonyms defined as:

arse (noun)	tail end (noun)
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	any projection that resembles the tail of an animal
	the time of the last part of something