adherent vs follower

adherent and follower both are nouns.

Word	Noun	Adjective	Verb	Adverb
adherent	Yes	Yes	No	No
follower	Yes	No	No	No

As nouns, follower is a hypernym of adherent; that is, follower is a word with a broader meaning than adherent:

adherent (noun)	follower (noun)
someone who believes and helps to spread the doctrine of another	a person who accepts the leadership of another
	someone who travels behind or pursues another

adherent (adjective)	follower (adjective)
sticking fast