book lover vs scholar

book lover and scholar both are nouns.

Word	Noun	Adjective	Verb	Adverb
book lover	Yes	No	No	No
scholar	Yes	No	No	No

As nouns, scholar is a hypernym of book lover; that is, scholar is a word with a broader meaning than book lover:

book lover: someone who loves (and usually collects) books
scholar: a learned person; someone who by long study has gained mastery in one or more disciplines

Other hypernyms of book lover include bookman, scholarly person.

book lover (noun)	scholar (noun)
someone who loves (and usually collects) books	a learned person; someone who by long study has gained mastery in one or more disciplines
	someone (especially a child) who learns (as from a teacher) or takes up knowledge or beliefs
	a student who holds a scholarship