revel vs unhappiness

revel

noun
  • A kind of dance. 

  • An instance of merrymaking; a celebration. 

  • A wake for the dead. 

verb
  • To make merry; to have a happy, lively time. 

  • To take delight (in something). 

unhappiness

noun
  • The feeling of not being happy 

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