adversity vs unluck

adversity

noun
  • The state of adverse conditions; state of misfortune or calamity. 

  • An event that is adverse; calamity. 

unluck

noun
  • Absence or lack of luck; lucklessness; bad luck; misfortune. 

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