peacekeeper vs police officer

peacekeeper

noun
  • An officer of the peace (police officer) in a force run by a Canadian aboriginal community. 

  • One that preserves the peace. 

  • A member of a military force charged with peacekeeping duties in a troublespot. 

police officer

noun
  • A peace officer who is a member of a police force. 

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