giveaway vs warning sign

giveaway

noun
  • An indicator that makes something obvious or apparent. 

  • The act of giving something away for free. 

  • Something that is given away or handed out for free. 

  • An event at which things are given away for free. 

adj
  • free of charge, at no cost. 

  • very low. 

warning sign

noun
  • An indication that someone or something is in danger or at risk 

  • A sign that indicates a danger, for example to vehicles on a road or of hazardous chemicals. 

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