rear end vs dirty word

rear end and dirty word both are nouns.

Word	Noun	Adjective	Verb	Adverb
rear end	Yes	No	No	No
dirty word	Yes	No	No	No

rear end (noun)	dirty word (noun)
the fleshy part of the human body that you sit on	an offensive or indecent word or phrase
	a word that is considered to be unmentionable