graybeard vs patriarch

graybeard and patriarch both are nouns.

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

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

Other hyponyms of graybeard include codger, old codger, antique, gaffer, old-timer, old geezer, oldtimer.

graybeard (noun)	patriarch (noun)
a man who is very old	the male head of family or tribe
	any of the early biblical characters regarded as fathers of the human race
	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