boredom vs lassitude

boredom

noun
  • An instance or period of being bored; A bored state. 

  • The state of being bored. 

lassitude

noun
  • Listlessness or languor. 

  • Lethargy or lack of energy; fatigue. 

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