The Collaborative International Dictionary of English v.0.48:
greybeard \grey"beard\ n. a man who is old. Syn: old man. [WordNet 1.5]WordNet (r) 3.0 (2006):
greybeard n 1: a man who is very old [syn: old man, greybeard, graybeard, Methuselah] 2: a stoneware drinking jug with a long neck; decorated with a caricature of Cardinal Bellarmine (17th century) [syn: bellarmine, longbeard, long-beard, greybeard]