dirty word vs dysphemism

dirty word

noun
  • A word that is considered vulgar, not necessarily sexual in nature. 

  • The name of a topic that a person does not like to hear or discuss. 

dysphemism

noun
  • The use of a word or phrase carrying negative connotations or imagery (especially one that is derogatory, offensive or vulgar) to replace a (more) neutral original. 

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

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