The Collaborative International Dictionary of English v.0.48:

Fishwife \Fish"wife`\, n.
   1. A fishwoman.
      [1913 Webster]

   2. A woman who abusively scolds other people, often using
      coarse or vulgar language.
      [PJC]

WordNet (r) 3.0 (2006):

fishwife
    n 1: someone who sells fish [syn: fishmonger, fishwife]

Moby Thesaurus II by Grady Ward, 1.0:

51 Moby Thesaurus words for "fishwife":
   Xanthippe, amazon, baker, battle-ax, beldam, bitch, bookdealer,
   bookseller, butcher, cat, chandler, clothing merchant,
   common scold, confectioner, draper, drysalter, fishmonger, florist,
   footwear merchant, fruiterer, furnisher, furrier, fury,
   greengrocer, grocer, groceryman, haberdasher, hardwareman, harpy,
   ironmonger, jeweler, liquor merchant, newsdealer, ogress, perfumer,
   poulterer, saddler, scold, she-devil, she-wolf, shrew, spitfire,
   stationer, termagant, tigress, tobacconist, vintner, virago, vixen,
   wine merchant, witch