heretical vs dissident

heretical is not a noun while dissident is a noun.

Word	Noun	Adjective	Verb	Adverb
heretical	No	Yes	No	No
dissident	Yes	Yes	No	No

As adjectives, heretical and dissident are synonyms defined as:

heretical and dissident: characterized by departure from accepted beliefs or standards

Other synonyms of heretical include heterodox.

heretical (noun)	dissident (noun)
	a person who dissents from some established policy

heretical (adjective)	dissident (adjective)
characterized by departure from accepted beliefs or standards	disagreeing, especially with a majority
	characterized by departure from accepted beliefs or standards