bargainer vs art dealer

bargainer and art dealer both are nouns.

Word	Noun	Adjective	Verb	Adverb
bargainer	Yes	No	No	No
art dealer	Yes	No	No	No

As nouns, art dealer is a hyponym of bargainer; that is, art dealer is a word with a more specific, narrower meaning than bargainer:

bargainer: someone who purchases and maintains an inventory of goods to be sold
art dealer: a dealer in works of art requiring esthetic evaluation

bargainer (noun)	art dealer (noun)
someone who purchases and maintains an inventory of goods to be sold	a dealer in works of art requiring esthetic evaluation
negotiator of the terms of a transaction