foretoken vs threaten

foretoken

verb
  • To betoken beforehand; prognosticate; foreshadow; give warning of; presage. 

noun
  • A prognostic; a premonitory sign; warning or presentiment. 

threaten

verb
  • To portend, or give a warning of. 

  • To call into question the validity of (a belief, idea, or viewpoint); to challenge. 

  • He threatened me with a knife. 

  • To make a threat against someone; to use threats. 

  • To menace, or be dangerous. 

  • To be close to equaling or surpassing (a record, etc.) 

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