jug vs greybeard

jug and greybeard both are nouns.

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

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

jug: a large bottle with a narrow mouth
greybeard: a stoneware drinking jug with a long neck; decorated with a caricature of Cardinal Bellarmine (17th century)

Other hyponyms of jug include bellarmine, long-beard, longbeard, water jug, whiskey jug.

jug (noun)	greybeard (noun)
a large bottle with a narrow mouth	a stoneware drinking jug with a long neck; decorated with a caricature of Cardinal Bellarmine (17th century)
the quantity contained in a jug	a man who is very old

jug (verb)	greybeard (verb)
stew in an earthenware jug
lock up or confine, in or as in a jail