twat vs female genitals

twat and female genitals both are nouns.

Word	Noun	Adjective	Verb	Adverb
twat	Yes	No	No	No
female genitals	Yes	No	No	No

As nouns, female genitals is a hypernym of twat; that is, female genitals is a word with a broader meaning than twat:

Other hypernyms of twat include fanny, female genital organ, female genitalia.

twat (noun)	female genitals (noun)
obscene terms for female genitals	external female sex organs
a man who is a stupid incompetent fool