danger signal vs injunction

danger signal

noun
  • A signal set at danger and showing a red light or other stop indication, which a train driver must not pass until it changes or until manually cleared past the signal by a dispatcher. 

  • An indication that a potentially bad or dangerous situation could develop. 

injunction

noun
  • The act of enjoining; the act of directing, commanding, or prohibiting. 

  • A writ or process, granted by a court of equity, and, in some cases, under statutes, by a court of law, whereby a party is required to do or to refrain from doing certain acts, according to the exigency of the writ. 

  • That which is enjoined; such as an order, mandate, decree, command, precept. 

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