blackball vs keep at arm's length

blackball

verb
  • To ostracize. 

  • To vote against, especially in an exclusive organization. 

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. 

keep at arm's length

verb
  • Avoid direct confrontation or struggle. 

  • Avoid a close relationship. 

  • Keep at a distance, away from one's body. 

How often have the words blackball and keep at arm's length occurred in a corpus of books? (source: Google Ngram Viewer )