japer vs jester

japer

noun
  • One who japes; a joker. 

jester

noun
  • One who jests, jokes or teases. 

  • A person in colourful garb and fool's cap who amused a medieval and early modern royal or noble court. 

  • Any of various nymphalid butterflies of the Southeast Asian genus Symbrenthia. 

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