aggression vs diffidence

aggression

noun
  • Hostile or destructive behavior or actions. 

  • The practice or habit of launching attacks. 

  • The act of initiating hostilities or invasion. 

diffidence

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

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