leatherneck vs navigator

leatherneck

noun
  • Specifically, a marine. 

  • A soldier. 

navigator

noun
  • A sea explorer. 

  • A device that navigates an aircraft, automobile or missile. 

  • A person who navigates, especially an officer with that responsibility on a ship or an aircrew member with that responsibility on an aircraft. 

  • A user interface that allows navigating through a structure of any kind. 

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