ennui vs vigour

ennui

noun
  • A gripping listlessness or melancholia caused by boredom; depression. 

verb
  • To make bored or listless; to weary. 

vigour

noun
  • Strength or force in animal or vegetable nature or action. 

  • Strength; efficacy; potency. 

  • Active strength or force of body or mind; capacity for exertion, physically, intellectually, or morally; energy. 

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