class fellow vs friend

class fellow and friend both are nouns.

Word	Noun	Adjective	Verb	Adverb
class fellow	Yes	No	No	No
friend	Yes	No	No	No

As nouns, friend is a hypernym of class fellow; that is, friend is a word with a broader meaning than class fellow:

Other hypernyms of class fellow include acquaintance.

class fellow (noun)	friend (noun)
an acquaintance that you go to school with	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.