audacity vs diffidence

audacity

noun
  • Insolent boldness, especially when imprudent or unconventional. 

  • Fearlessness, intrepidity or daring, especially with confident disregard for personal safety, conventional thought, or other restrictions. 

diffidence

noun
  • The state of being diffident, timid or shy; reticence or self-effacement. 

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