Gnosticism vs heresy

Gnosticism and heresy both are nouns.

Word	Noun	Adjective	Verb	Adverb
Gnosticism	Yes	No	No	No
heresy	Yes	No	No	No

As nouns, heresy is a hypernym of Gnosticism; that is, heresy is a word with a broader meaning than Gnosticism:

Gnosticism: a religious orientation advocating gnosis as the way to release a person's spiritual element; considered heresy by Christian churches
heresy: a belief that rejects the orthodox tenets of a religion

Other hypernyms of Gnosticism include unorthodoxy, theological doctrine.

Gnosticism (noun)	heresy (noun)
a religious orientation advocating gnosis as the way to release a person's spiritual element; considered heresy by Christian churches	a belief that rejects the orthodox tenets of a religion
	any opinions or doctrines at variance with the official or orthodox position