patriarch vs greybeard

patriarch and greybeard both are nouns.

Word	Noun	Adjective	Verb	Adverb
patriarch	Yes	No	No	No
greybeard	Yes	No	No	No

As nouns, greybeard is a hypernym of patriarch; that is, greybeard is a word with a broader meaning than patriarch:

Other hypernyms of patriarch include graybeard, Methuselah, old man.

patriarch (noun)	greybeard (noun)
the male head of family or tribe	a stoneware drinking jug with a long neck; decorated with a caricature of Cardinal Bellarmine (17th century)
any of the early biblical characters regarded as fathers of the human race	a man who is very old
title for the heads of the Eastern Orthodox Churches (in Istanbul and Alexandria and Moscow and Jerusalem)
a man who is older and higher in rank than yourself