The Collaborative International Dictionary of English v.0.48:

Graybeard \Gray"beard`\, n.
   An old man. --Shak.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Bellarmine \Bel"lar*mine\, n.
   A stoneware jug of a pattern originated in the neighborhood
   of Cologne, Germany, in the 16th century. It has a bearded
   face or mask supposed to represent Cardinal Bellarmine, a
   leader in the Roman Catholic Counter Reformation, following
   the Reformation; -- called also graybeard, longbeard.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

graybeard
    n 1: a man who is very old [syn: old man, greybeard,
         graybeard, Methuselah]

Moby Thesaurus II by Grady Ward, 1.0:

39 Moby Thesaurus words for "graybeard":
   Father Time, Methuselah, Nestor, Old Paar, centenarian, dotard,
   elder, gaffer, geezer, golden-ager, gramps, grandfather, grandsire,
   gray-headed person, grayhair, grisard, nonagenarian, octogenarian,
   old chap, old codger, old dog, old duffer, old geezer, old gent,
   old gentleman, old man, old party, old-timer, older, oldster,
   pantaloon, patriarch, presbyter, senior citizen, septuagenarian,
   sexagenarian, the quiet-voiced elders, venerable sir, veteran