innuendo vs secret message

innuendo

verb
  • To interpret (something libellous or slanderous) in terms of what was implied. 

noun
  • Part of a pleading in cases of libel and slander, pointing out what and who was meant by the libellous matter or description. 

  • She made a devious innuendo about her husband, who was embarrassed. 

  • A derogatory hint or reference to a person or thing. An implication, intimation or insinuation. 

  • A rhetorical device with an omitted, but obvious conclusion, made to increase the force of an argument. 

secret message

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