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]