one of the boys vs boy

one of the boys and boy both are nouns.

Word	Noun	Adjective	Verb	Adverb
one of the boys	Yes	No	No	No
boy	Yes	No	No	No

As nouns, boy is a hypernym of one of the boys; that is, boy is a word with a broader meaning than one of the boys:

one of the boys: a man who has been socially accepted into a group of other men
boy: a friendly informal reference to a grown man

one of the boys (noun)	boy (noun)
a man who has been socially accepted into a group of other men	a youthful male person
	(ethnic slur) offensive and disparaging term for Black man
	a friendly informal reference to a grown man
	a male human offspring