corroboration vs gainsaying

corroboration

noun
  • That which corroborates. 

  • The act of corroborating, strengthening, or confirming; addition of strength; confirmation 

gainsaying

noun
  • Denial; denying. 

  • Rebellious opposition; rebellion. 

  • Refusal to accept or believe something. 

  • Contradiction. 

  • Opposition, especially in speech. 

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