mackerel vs souteneur

mackerel

noun
  • Certain smaller edible fish, principally true mackerel and Spanish mackerel in family Scombridae, often speckled, 

  • typically Scomber scombrus in the British isles. 

  • Certain other similar small fish in families Carangidae, Gempylidae, and Hexagrammidae. 

  • A true mackerel, any fish of tribe Scombrini (Scomber spp., Rastrelliger spp.) 

souteneur

noun
  • A man who protects a prostitute and lives off her earnings; a pimp. 

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