obviousness vs patency

obviousness

noun
  • The characteristic of being obvious. 

patency

noun
  • Obviousness; clarity. 

  • The condition or state of being patent. 

  • The degree of openness (of a tube, such as a blood vessel or catheter); the relative absence of blockage or obstruction. Measured in percent. 

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