female genitals vs twat

female genitals and twat both are nouns.

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

As nouns, twat is a hyponym of female genitals; that is, twat is a word with a more specific, narrower meaning than female genitals:

Other hyponyms of female genitals include minge, cunt, puss, pussy, slit, snatch, vulva.

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