assassin vs exterminator

assassin

noun
  • Someone who intentionally kills a person, especially a professional who kills a public or political figure. 

  • Any ruthless killer. 

  • A member of the Nizari Ismaili Muslim community of the Alamut Period. 

verb
  • To assassinate. 

exterminator

noun
  • Someone or something that exterminates. 

  • Specifically, a person whose job it is to kill insects and other pests in a building. 

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