friend vs admirer

friend and admirer both are nouns.

Word	Noun	Adjective	Verb	Adverb
friend	Yes	No	No	No
admirer	Yes	No	No	No

As nouns, friend and admirer are synonyms defined as:

Other synonyms of friend include booster, champion, protagonist, supporter.

friend (noun)	admirer (noun)
a person you know well and regard with affection and trust	someone who admires a young woman
a person with whom you are acquainted	a person who backs a politician or a team etc.
an associate who provides cooperation or assistance	a person who admires; someone who esteems or respects or approves
a person who backs a politician or a team etc.