book fair vs fair

book fair and fair both are nouns.

Word	Noun	Adjective	Verb	Adverb
book fair	Yes	No	No	No
fair	Yes	Yes	Yes	Yes

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

book fair: bazaar at which books are sold or auctioned off in order to raise funds for a worthy cause
fair: a sale of miscellany; often for charity

Other hypernyms of book fair include bazaar.

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

book fair: fair organized by publishers or booksellers to promote the sale of books
fair: gathering of producers to promote business

book fair (noun)	fair (noun)
bazaar at which books are sold or auctioned off in order to raise funds for a worthy cause	a sale of miscellany; often for charity
fair organized by publishers or booksellers to promote the sale of books	a traveling show; having sideshows and rides and games of skill etc.
	a competitive exhibition of farm products
	gathering of producers to promote business

book fair (adjective)	fair (adjective)
	(of a baseball) hit between the foul lines
	free from favoritism or self-interest or bias or deception; conforming with established standards or rules
	very pleasing to the eye
	(used of hair or skin) pale or light-colored
	free of clouds or rain
	gained or earned without cheating or stealing
	attractively feminine
	(of a manuscript) having few alterations or corrections
	not excessive or extreme
	lacking exceptional quality or ability

book fair (verb)	fair (verb)
	join so that the external surfaces blend smoothly

book fair (adverb)	fair (adverb)
	without favoring one party, in a fair evenhanded manner
	in conformity with the rules or laws and without fraud or cheating