jouster vs mercenary

jouster

noun
  • A horse used as a mount when jousting. 

  • A person who jousts. 

mercenary

noun
  • A person employed to fight in an armed conflict who is not a member of the state or military group for which they are fighting and whose primary motivation is private gain. 

  • One hired to engage in a figurative battle, as a corporate takeover, a lawsuit, or a political campaign. 

adj
  • Motivated by private gain. 

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