affirmation vs disaffirmation

affirmation

noun
  • A form of self-forced meditation or repetition; autosuggestion. 

  • That which is affirmed; a declaration that something is true. 

  • The solemn declaration made by Quakers and others incapable of taking an oath. 

disaffirmation

noun
  • The act of denial; a declaration that something is not true. 

  • Repudiation of self or other. 

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