octogenarian

octogenarian
    adj 1: being from 80 to 89 years old
    n 1: someone whose age is in the eighties
    

Octogenarian \Oc`to*ge*na"ri*an\, n.
   A person eighty years, or more, of age.
   [1913 Webster]
    

84 Moby Thesaurus words for "octogenarian":
      Father Time, L, Methuselah, Nestor, Old Paar, Sexagesima, boxcar,
      boxcars, centenarian, dotard, dozen, duodecimo, eighty, elder,
      eleven, fifteen, fifty, five and twenty, fortnight, forty,
      four and twenty, fourscore, fourscore and ten, fourteen, gaffer,
      geezer, golden-ager, gramps, grandfather, grandsire, graybeard,
      half a hundred, long dozen, ninety, nonagenarian, 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, quindecennial, quindecim,
      quindecima, quindene, score, senior citizen, septuagenarian,
      seventy, sexagenarian, sexagenary, sexagesimo-quarto, sixteen,
      sixteenmo, sixty, sixty-four, sixty-fourmo, teens,
      the quiet-voiced elders, thirteen, thirty-two, thirty-twomo,
      threescore, threescore and ten, twelve, twelvemo, twenty,
      twenty-five, twenty-four, twenty-fourmo, two dozen, two weeks,
      twoscore, venerable sir, veteran