ransom vs slush fund

ransom

noun
  • Money paid for the freeing of a hostage. 

  • The release of a captive, or of captured property, by payment of a consideration. 

  • A sum paid for the pardon of some great offence and the discharge of the offender; also, a fine paid in lieu of corporal punishment. 

verb
  • To exact a ransom (payment) in exchange for the freedom of. 

  • To pay a price to set someone free from captivity or punishment. 

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 ransom and slush fund occurred in a corpus of books? (source: Google Ngram Viewer )