enforcer vs executioner

enforcer

noun
  • One who enforces. 

  • The member of a group, especially of a gang, charged with keeping dissident members obedient. 

  • A hired strongman, especially working for the underworld. 

  • A player who physically intimidates or confronts the opposition. 

executioner

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

  • A hit man, especially being in some organization. 

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