near-synonym vs synonymy

near-synonym

noun
  • A term whose meaning is similar, but not identical, to that of another term. 

synonymy

noun
  • A system of synonyms. 

  • The collective synonyms (all the names referring to a particular taxon, except the correct name) 

  • The state of not being a correct name, of being a synonym 

  • The quality of being synonymous; sameness of meaning. 

  • A list or collection of synonyms, often compared and contrasted. 

  • The study of synonyms. 

  • The collective synonyms (all the names referring to the same taxon, including the correct name) 

How often have the words near-synonym and synonymy occurred in a corpus of books? (source: Google Ngram Viewer )