dealer vs fishwife

dealer and fishwife both are nouns.

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

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

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

dealer (noun)	fishwife (noun)
a firm engaged in trading	someone who sells fish
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