English Etymology From patent + -cy. Pronunciation IPA(key): /ˈpeɪtənsi/ Noun patency (plural patencies) (medicine) The condition or state of being patent. Antonyms: impatency, imperforation, atresia, occlusion (medicine) The degree of openness (of a tube, such as a blood vessel or catheter); the relative absence of blockage or obstruction. Measured in percent. Antonym: obstruction (uncountable) Obviousness; clarity.Wikiwand - on Seamless Wikipedia browsing. On steroids.