executioner vs hangman

executioner

noun
  • An official person who carries out the capital punishment of a criminal. 

  • A hit man, especially being in some organization. 

hangman

noun
  • An executioner responsible for hanging criminals. 

  • Someone responsible for hanging pictures and other artworks in a gallery, museum etc. 

  • A guessing game where one has to guess the word an opponent is thinking of by guessing one letter at a time, and involving the gradual drawing of a stick figure hanging from the gallows. 

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