fitch vs polecat

fitch

noun
  • A polecat, such as the European polecat (Mustela putorius), the striped polecat, steppe polecat, or black-footed polecat of America. 

  • A skin of a polecat. 

polecat

noun
  • notably, the European polecat, Mustela putorius. 

  • A tubular device used to support lights on a set. 

  • A weasel-like animal of the genus Mustela. 

  • A skunk. 

How often have the words fitch and polecat occurred in a corpus of books? (source: Google Ngram Viewer )