sexual inversion vs gayness

sexual inversion and gayness both are nouns.

Word	Noun	Adjective	Verb	Adverb
sexual inversion	Yes	No	No	No
gayness	Yes	No	No	No

As nouns, gayness is a hypernym of sexual inversion; that is, gayness is a word with a broader meaning than sexual inversion:

sexual inversion: a term formerly used to mean taking on the gender role of the opposite sex
gayness: a sexual attraction to (or sexual relations with) persons of the same sex

Other hypernyms of sexual inversion include homoeroticism, homosexualism, homosexuality, queerness.

sexual inversion (noun)	gayness (noun)
a term formerly used to mean taking on the gender role of the opposite sex	a sexual attraction to (or sexual relations with) persons of the same sex