contradiction vs exaction

contradiction

noun
  • A statement that contradicts itself, i.e., a statement that claims that the same thing is true and that it is false at the same time and in the same senses of the terms. 

  • A logical inconsistency among two or more elements or propositions. 

  • The act of contradicting. 

  • A proposition that is false for all values of its propositional variables or Boolean atoms. 

exaction

noun
  • The act of demanding with authority, and compelling to pay or yield; compulsion to give or furnish; a levying by force 

  • extortion. 

  • That which is exacted; a severe tribute; a fee, reward, or contribution, demanded or levied with severity or injustice. 

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