patency vs plainness

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. 

plainness

noun
  • The condition of being plain (in all senses) 

  • The product or result of being plain 

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