invitation vs warning

invitation

noun
  • A document or verbal message conveying an invitation. 

  • The act of inviting; solicitation; the requesting of a person's company. 

  • A bid that tells one's partner that game or slam is likely if their hand is at the strong end of what they have indicated. 

  • Allurement; enticement. 

  • A line that is intentionally left open to encourage the opponent to attack. 

  • The brief exhortation introducing the confession in the Anglican communion-office. 

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 invitation and warning occurred in a corpus of books? (source: Google Ngram Viewer )