ennui vs indifference

ennui

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

verb
  • To make bored or listless; to weary. 

indifference

noun
  • Unemotional apathy. 

  • Unconcerned nonchalance. 

  • The state of being indifferent. 

  • Unbiased impartiality. 

  • Self-identity defined through the negation of difference, non-difference. 

  • A lack of enthusiasm. 

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