crotch vs genital organ

crotch and genital organ both are nouns.

Word	Noun	Adjective	Verb	Adverb
crotch	Yes	No	No	No
genital organ	Yes	No	No	No

As nouns, crotch and genital organ are synonyms defined as:

Other synonyms of crotch include genitalia, genitals, private parts, privates.

crotch (noun)	genital organ (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