euphemism vs tropology

euphemism

noun
  • A word or phrase that is used to replace another in this way. 

  • The use of a word or phrase to replace another with one that is considered less offensive, blunt or vulgar than the word or phrase which it replaces. 

tropology

noun
  • The use of a trope (metaphor or figure of speech). 

  • The interpretation of scripture or other work in order to educe moral or figurative meaning; a treatise of such interpretation. 

  • A recurring motif or metaphor, a trope; an interplay of tropes. 

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