harm vs weaken

harm

verb
  • To cause injury to another; to hurt; to cause damage to something. 

noun
  • detriment; misfortune. 

  • physical injury; hurt; damage 

  • That which causes injury, damage, or loss. 

  • emotional or figurative hurt 

weaken

verb
  • To make weaker or less strong. 

  • To become weaker or less strong. 

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