Hadean vs gloomy

Hadean

adj
  • Pertaining to Hades or hell. 

  • Of, or relating to the geological eon. 

name
  • The Hadean eon; part of the Precambrian supereon, spanning from around 4.6 to 4 billion years ago. 

gloomy

adj
  • Suffering from gloom; melancholy; dejected. 

  • Not very illuminated; dim because of darkness, especially when appearing depressing or frightening. 

noun
  • Someone or something that is gloomy or pessimistic. 

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