head-to-head vs warring

head-to-head

adj

  • Direct, one-to-one. 

adv

  • Directly, one-to-one. 

  • Facing one another. 

warring

adj

  • engaged in war; belligerent 

noun

  • The act of engaging in war or conflict. 

How often have the words head-to-head and warring occurred in a corpus of books? (source: Google Ngram Viewer )