double-cross vs fool

double-cross

verb
  • To betray or go back on. 

  • To cross twice in hybridization, as (A × B) × (C × D); for example, in commercial hybrid seed corn, A through D are classically inbreds, and their grandoffspring is the seed for sale. 

fool

verb
  • To trick; to deceive. 

  • To act in an idiotic manner; to act foolishly. 

noun
  • A type of dessert made of puréed fruit and custard or cream. 

  • A jester; a person whose role was to entertain a sovereign and the court (or lower personages). 

  • A person with poor judgment or little intelligence. 

  • A particular card in a tarot deck, representing a jester. 

  • Someone who derives pleasure from something specified. 

  • Buddy, dude, man. 

adj
  • Foolish. 

How often have the words double-cross and fool occurred in a corpus of books? (source: Google Ngram Viewer )