falsity vs self-contradiction

falsity

noun
  • Something that is false; an untrue assertion. 

  • The falsity of that statement is easily proven. 

  • The characteristic of being untrue. 

self-contradiction

noun
  • A statement that contains a contradiction, or a premise from which one could be derived 

How often have the words falsity and self-contradiction occurred in a corpus of books? (source: Google Ngram Viewer )