heroism vs qualm

heroism

noun
  • The qualities characteristic of a hero, such as courage, bravery, fortitude, selflessness, etc.; the display of such qualities. 

qualm

verb
  • To have a sickly feeling. 

noun
  • A prick of the conscience; a moral scruple, a pang of guilt. 

  • A feeling of apprehension, doubt, fear etc. 

  • A sudden sickly feeling; queasiness. 

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