gentleness vs sadism

gentleness

noun
  • The state of being gentle. 

sadism

noun
  • Achievement of sexual gratification by inflicting pain or humiliation on others, or watching pain or humiliation inflicted on others. 

  • Deliberate or wanton cruelty, either mental or physical, to other people, or to animals, regardless of whether for (sexual) gratification. 

  • The enjoyment of inflicting pain or humiliation without pity. 

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