disuse vs lassitude

disuse

noun

  • The state of not being used; neglect. 

verb

  • To cease the use of. 

lassitude

noun

  • Listlessness or languor. 

  • Lethargy or lack of energy; fatigue. 

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