energize vs ennui

energize

verb
  • To invigorate; to make energetic. 

  • To supply with energy, especially electricity; to turn on power to (something). 

ennui

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

verb
  • To make bored or listless; to weary. 

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