green light vs sanction

green light

noun
  • Approval, or permission to proceed. 

  • A go-ahead to commit a crime, specifically to carry out a hit on someone (i.e. to kill). 

  • A traffic light in its green state (indicating that vehicles may proceed). 

sanction

noun
  • An approval, by an authority, generally one that makes something valid. 

  • A penalty, punishment, or some coercive measure, intended to ensure compliance; especially one adopted by several nations, or by an international body. 

  • A law, treaty, or contract, or a clause within a law, treaty, or contract, specifying any of the above. 

verb
  • To penalize (a state etc.) with sanctions. 

  • To ratify; to make valid. 

  • To give official authorization or approval to; to countenance. 

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