patency vs apparency

patency and apparency both are nouns.

Word	Noun	Adjective	Verb	Adverb
patency	Yes	No	No	No
apparency	Yes	No	No	No

As nouns, apparency is a hyponym of patency; that is, apparency is a word with a more specific, narrower meaning than patency:

Other hyponyms of patency include apparentness, blatancy, predominance, predomination.

patency (noun)	apparency (noun)
the openness (lack of obstruction) of a bodily passage or duct	the property of being apparent
the property of being easy to see and understand