affaire d'honneur vs mano a mano

affaire d'honneur

noun

  • A duel. 

mano a mano

noun

  • A head-on conflict or direct competition. 

adj

  • in close confrontation 

adv

  • Characterized by head-to-head competition or conflict. 

How often have the words affaire d'honneur and mano a mano occurred in a corpus of books? (source: Google Ngram Viewer )