Judaism vs tref

Judaism is a noun but tref is not a noun.

Word	Noun	Adjective	Verb	Adverb
Judaism	Yes	No	No	No
tref	No	Yes	No	No

Judaism (noun)	tref (noun)
the monotheistic religion of the Jews having its spiritual and ethical principles embodied chiefly in the Torah and in the Talmud
Jews collectively who practice a religion based on the Torah and the Talmud

Judaism (adjective)	tref (adjective)
	not conforming to dietary laws