crotch vs genitalia

crotch and genitalia both are nouns.

Word	Noun	Adjective	Verb	Adverb
crotch	Yes	No	No	No
genitalia	Yes	No	No	No

As nouns, crotch and genitalia are synonyms defined as:

Other synonyms of crotch include genital organ, genitals, private parts, privates.

crotch (noun)	genitalia (noun)
the angle formed by the inner sides of the legs where they join the human trunk	external sex organ
external sex organ
the region of the angle formed by the junction of two branches