green light vs rubber stamp

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). 

rubber stamp

noun
  • A person or organisation that approves, routinely or as a formality, matters decided by some other person or organisation. 

  • A piece of rubber or similar material with a design or text carved or molded for the purpose of transferring ink or dye to imprint that design on another object. 

adj
  • Of a person, organisation, or process, making decisions or approving matters routinely or without real power. 

verb
  • To process, approve or decide matters routinely rather than through careful consideration. 

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