bibliopolist vs trader

bibliopolist and trader both are nouns.

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

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

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

Other hypernyms of bibliopolist include bargainer, dealer, monger.

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