WordNet (r) 3.0 (2006):

Methuselah
    n 1: (Old Testament) a patriarch (grandfather of Noah) who is
         said to have lived 969 years
    2: a man who is very old [syn: old man, greybeard,
       graybeard, Methuselah]

Moby Thesaurus II by Grady Ward, 1.0:

67 Moby Thesaurus words for "Methuselah":
   Father Time, Nestor, Old Paar, antediluvian, antique, back number,
   centenarian, conservative, dad, dodo, dotard, elder, fogy, fossil,
   fud, fuddy-duddy, gaffer, geezer, golden-ager, gramps, grandfather,
   grandsire, granny, graybeard, has-been, longhair, matriarch,
   mid-Victorian, mossback, nonagenarian, octogenarian, old believer,
   old chap, old codger, old crock, old dodo, old dog, old duffer,
   old fogy, old geezer, old gent, old gentleman, old liner, old man,
   old party, old poop, old woman, old-timer, older, oldster,
   pantaloon, patriarch, pop, pops, presbyter, reactionary,
   regular old fogy, relic, senior citizen, septuagenarian,
   sexagenarian, square, starets, the quiet-voiced elders,
   traditionalist, venerable sir, veteran



Easton's 1897 Bible Dictionary:

Methuselah
   man of the dart, the son of Enoch, and grandfather of Noah. He
   was the oldest man of whom we have any record, dying at the age
   of nine hundred and sixty-nine years, in the year of the Flood
   (Gen. 5:21-27; 1 Chr. 1:3).