blackball vs denialism

blackball

noun
  • A rejection; a vote against admitting someone. 

  • A black ball used to indicate such a negative vote. 

  • A kind of large black sweet; a niggerball. 

  • A game, a standardized version of the English version of eight-ball. 

  • A substance for blacking shoes, boots, etc. or for taking impressions of engraved work. 

verb
  • To ostracize. 

  • To vote against, especially in an exclusive organization. 

denialism

noun
  • The practice of rejecting propositions which are strongly supported by scientific or historical evidence, and often of seeking to influence policy processes and outcomes accordingly. 

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