fanny vs female genitalia

fanny and female genitalia both are nouns.

Word	Noun	Adjective	Verb	Adverb
fanny	Yes	No	No	No
female genitalia	Yes	No	No	No

As nouns, fanny and female genitalia are synonyms defined as:

Other synonyms of fanny include female genital organ, female genitals.

fanny (noun)	female genitalia (noun)
the fleshy part of the human body that you sit on	external female sex organs
external female sex organs