oversight vs unhappiness

oversight

noun
  • An omission; something that is left out, missed or forgotten. 

  • Supervision or management. 

  • Overview. 

verb
  • To suppress content in a way that removes or minimizes its visibility or viewability. 

  • To oversee; to supervise. 

unhappiness

noun
  • The feeling of not being happy 

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