derriere vs tail end

derriere and tail end both are nouns.

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

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

derriere and tail end: the fleshy part of the human body that you sit on

derriere (noun)	tail end (noun)
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