fishwife vs bargainer

fishwife and bargainer both are nouns.

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

As nouns, bargainer is a hypernym of fishwife; that is, bargainer is a word with a broader meaning than fishwife:

fishwife: someone who sells fish
bargainer: someone who purchases and maintains an inventory of goods to be sold

Other hypernyms of fishwife include dealer, monger, trader.

fishwife (noun)	bargainer (noun)
someone who sells fish	someone who purchases and maintains an inventory of goods to be sold
	negotiator of the terms of a transaction