button man vs pigsticker

button man

noun
  • A contract killer; a professional assassin. 

pigsticker

noun
  • A large knife, used as a weapon. 

  • A spike bayonet 

  • A hunter of wild boar. 

  • A pork butcher. 

  • A sled with a pointed front. 

  • A horse well-suited to hunt wild boar. 

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