executioner vs liquidator

executioner

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

  • A hit man, especially being in some organization. 

liquidator

noun
  • One who liquidates. 

  • Any of the workers involved in cleaning up the Chernobyl disaster 

  • One supporting the political policy of liquidationism; a liquidationist. 

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