well-wisher vs friend

well-wisher and friend both are nouns.

Word	Noun	Adjective	Verb	Adverb
well-wisher	Yes	No	No	No
friend	Yes	No	No	No

As nouns, friend is a hypernym of well-wisher; that is, friend is a word with a broader meaning than well-wisher:

well-wisher: someone who shares your feelings or opinions and hopes that you will be successful
friend: a person who backs a politician or a team etc.

Other hypernyms of well-wisher include admirer, booster, champion, protagonist, supporter.

well-wisher (noun)	friend (noun)
someone who shares your feelings or opinions and hopes that you will be successful	a person you know well and regard with affection and trust
	a person with whom you are acquainted
	an associate who provides cooperation or assistance
	a person who backs a politician or a team etc.