pederasty vs homosexualism

pederasty and homosexualism both are nouns.

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

As nouns, homosexualism is a hypernym of pederasty; that is, homosexualism is a word with a broader meaning than pederasty:

pederasty: sexual relations between a man and a boy (usually anal intercourse with the boy as a passive partner)
homosexualism: a sexual attraction to (or sexual relations with) persons of the same sex

Other hypernyms of pederasty include paraphilia, gayness, homoeroticism, homosexuality, queerness.

pederasty (noun)	homosexualism (noun)
sexual relations between a man and a boy (usually anal intercourse with the boy as a passive partner)	a sexual attraction to (or sexual relations with) persons of the same sex