bibliopolist vs dealer

bibliopolist and dealer both are nouns.

Word	Noun	Adjective	Verb	Adverb
bibliopolist	Yes	No	No	No
dealer	Yes	No	No	No

As nouns, dealer is a hypernym of bibliopolist; that is, dealer is a word with a broader meaning than bibliopolist:

bibliopolist: a dealer in secondhand books (especially rare or curious books)
dealer: someone who purchases and maintains an inventory of goods to be sold

Other hypernyms of bibliopolist include bargainer, monger, trader.

bibliopolist (noun)	dealer (noun)
a dealer in secondhand books (especially rare or curious books)	a firm engaged in trading
	a seller of illicit goods
	the person who distributes the playing cards in a card game
	someone who purchases and maintains an inventory of goods to be sold
	the major party to a financial transaction at a stock exchange; buys and sells for his own account