dirty word vs sweet Fanny Adams

dirty word and sweet Fanny Adams both are nouns.

Word	Noun	Adjective	Verb	Adverb
dirty word	Yes	No	No	No
sweet Fanny Adams	Yes	No	No	No

dirty word (noun)	sweet Fanny Adams (noun)
an offensive or indecent word or phrase	little or nothing at all
a word that is considered to be unmentionable