dissatisfaction vs ennui

dissatisfaction

noun
  • unhappiness or discontent 

  • the cause of such feelings 

ennui

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

verb
  • To make bored or listless; to weary. 

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