longbeard vs greybeard

longbeard and greybeard both are nouns.

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

As nouns, longbeard and greybeard are synonyms defined as:

longbeard and greybeard: a stoneware drinking jug with a long neck; decorated with a caricature of Cardinal Bellarmine (17th century)

Other synonyms of longbeard include bellarmine, long-beard.

longbeard (noun)	greybeard (noun)
a stoneware drinking jug with a long neck; decorated with a caricature of Cardinal Bellarmine (17th century)	a stoneware drinking jug with a long neck; decorated with a caricature of Cardinal Bellarmine (17th century)
	a man who is very old