malapropism vs vulgarism

malapropism

noun
  • The blundering use of an absurdly inappropriate word or expression in place of a similar-sounding one. 

  • An instance of this; malaprop. 

vulgarism

noun
  • A spelling, word, or phrase used in common speech that is considered improper or incorrect for formal communication. 

  • Editors of newspapers allow more vulgarisms to go to print today than they used to. 

  • A word or term that is considered offensive or vulgar. 

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