blackball vs endorsement

blackball

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

  • A rejection; a vote against admitting someone. 

  • 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. 

endorsement

noun
  • The act or quality of endorsing 

  • Sponsorship, in means of money, by a company, business or enterprise. 

  • An amendment or annotation to an insurance contract or other official document (such as a driving licence). 

  • An instructor's signed acknowledgement of time practising specific flying skills. 

  • Permission to carry out a specific skill or application in a field in which the practitioner already has a general licence. 

  • Support from an important, renowned figure of a media (celebrity, politics, sports, etc.), to get back up. 

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