blackmail vs slush fund

blackmail

noun
  • The extortion of money or favours by threats of public accusation, exposure, or censure. 

  • Black rent, or rent paid in corn, meat, or the lowest coin, as opposed to white rent, which was paid in silver. 

  • Compromising material that can be used to extort someone, dirt. 

verb
  • To extort money or favors from (a person) by exciting fears of injury other than bodily harm, such as injury to reputation, distress of mind, false accusation, etc. 

  • To speak ill of someone; to defame someone. 

slush fund

noun
  • Money stored for illegal or dishonest purposes. 

  • Money that has not been hypothecated or dedicated to a particular purpose, or which is used for a different purpose than originally intended. 

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