ennui vs sameness

ennui

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

verb
  • To make bored or listless; to weary. 

sameness

noun
  • A tiring lack of variety; monotony. 

  • The quality of being the same; identity. 

  • The state of being equivalent; equality. 

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