homosexualism vs gayness

homosexualism and gayness both are nouns.

Word	Noun	Adjective	Verb	Adverb
homosexualism	Yes	No	No	No
gayness	Yes	No	No	No

As nouns, homosexualism and gayness are synonyms defined as:

homosexualism and gayness: a sexual attraction to (or sexual relations with) persons of the same sex

Other synonyms of homosexualism include homoeroticism, homosexuality, queerness.

homosexualism (noun)	gayness (noun)
a sexual attraction to (or sexual relations with) persons of the same sex	a sexual attraction to (or sexual relations with) persons of the same sex