harm vs let-down

harm

noun
  • detriment; misfortune. 

  • physical injury; hurt; damage 

  • That which causes injury, damage, or loss. 

  • emotional or figurative hurt 

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

let-down

noun
  • A disappointment or anticlimax. 

  • The clearance of an aircraft to descend through clouds to clear air below, or the process of granting such a clearance. 

  • The neurohormonal release of milk in dairy cows or in breastfeeding human mothers. 

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