bargainer vs barterer

bargainer and barterer both are nouns.

Word	Noun	Adjective	Verb	Adverb
bargainer	Yes	No	No	No
barterer	Yes	No	No	No

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

bargainer: someone who purchases and maintains an inventory of goods to be sold
barterer: a trader who exchanges goods and not money

bargainer (noun)	barterer (noun)
someone who purchases and maintains an inventory of goods to be sold	a trader who exchanges goods and not money
negotiator of the terms of a transaction