apologist vs crusader

apologist

noun
  • One who speaks or writes in defense of a faith, a cause, or an institution. 

  • One who makes an apology. 

crusader

noun
  • A person engaged in a crusade. 

  • An American, especially a soldier or leader who wages war against Islamist militants. 

  • the crusaders of the Middle Ages 

  • A Westerner; a Christian, especially of European descent or a missionary. 

  • A fighter in the medieval Crusades who had taken the Cross. 

  • (either attributively or in the plural) The United States and its Western allies. 

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