giaour vs infidel

giaour

noun
  • A non-Muslim, especially a Christian, an infidel; especially as used by Turkish people with particular reference to Christians such as Greeks, Armenians, Bulgarians, Serbs and Assyrians. 

infidel

noun
  • One who does not believe in a certain religion. 

  • One with no religious beliefs. 

  • One who does not believe in a certain principle. 

adj
  • Rejecting a specific religion. 

  • Of, characteristic of, or relating to unbelievers or unbelief. 

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