discontent vs tranquility

discontent

verb
  • To deprive of contentment; to make uneasy; to dissatisfy. 

noun
  • Dissatisfaction. 

  • A longing for better times or circumstances. 

  • A discontented person; a malcontent. 

adj
  • Not content; discontented; dissatisfied. 

tranquility

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