connotation vs hidden meaning

connotation

noun
  • The attribute or aggregate of attributes connoted by a term, contrasted with denotation. 

  • A meaning of a word or phrase that is suggested or implied, as opposed to a denotation, or literal meaning. A characteristic of words or phrases, or of the contexts that words and phrases are used in. 

hidden meaning

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