bravo vs warning

bravo

noun
  • A shout of "bravo!" 

  • A hired soldier; an assassin; a desperado. 

verb
  • To cheer or applaud, especially by saying bravo! 

intj
  • Used to express acclaim, especially to a performer. 

warning

noun
  • Something spoken or written that is intended to warn. 

  • The action of the verb warn; an instance of warning someone. 

intj
  • Used to warn of danger in signs and notices. 

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