facetious vs gelastic

facetious

adj
  • Pleasantly humorous; jocular. 

  • Treating serious issues with (often deliberately) inappropriate humour; flippant. 

  • Of an idea or statement, humorously silly or counterproductive for the purpose of sarcastically advocating the opposite. 

gelastic

adj
  • Pertaining to laughter, used in laughing, or to be the subject of laughter. 

  • Relating to a particularly severe form of epileptic fit, in which there is a sudden burst of energy. 

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