The Collaborative International Dictionary of English v.0.48:

Notable \Not"a*ble\, a. [F. notable, L. notabilis, fr. notare to
   mark, nota mark, note. See 5th Note.]
   [1913 Webster]
   1. Capable of being noted; noticeable; plain; evident.
      [1913 Webster]

   2. Worthy of notice; remarkable; memorable; noted or
      distinguished; as, a notable event, person.
      [1913 Webster]

   Note: Notable in the sense of careful, thrifty, characterized
         by thrift and capacity (as, a notable housekeeper) is
         pronounced by many good orthoepists, n[o^]t"[.a]*b'l,
         the derivatives notableness, and notably, being also
         similarly pronounced with short o in the first
         syllable.
         [1913 Webster]

   3. Well-known; notorious. [Obs.] --Chaucer.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Notable \Not"a*ble\ (n[=o]t"[.a]*b'l), n.
   1. A person, or thing, of distinction.
      [1913 Webster]

   2. (French Hist.) One of a number of persons, before the
      revolution of 1789, chiefly of the higher orders,
      appointed by the king to constitute a representative body.
      [1913 Webster]

WordNet (r) 3.0 (2006):

notable
    adj 1: worthy of notice; "a noteworthy advance in cancer
           research" [syn: noteworthy, notable]
    2: widely known and esteemed; "a famous actor"; "a celebrated
       musician"; "a famed scientist"; "an illustrious judge"; "a
       notable historian"; "a renowned painter" [syn: celebrated,
       famed, far-famed, famous, illustrious, notable,
       noted, renowned]
    n 1: a celebrity who is an inspiration to others; "he was host
         to a large gathering of luminaries" [syn: luminary,
         leading light, guiding light, notable, notability]

Moby Thesaurus II by Grady Ward, 1.0:

183 Moby Thesaurus words for "notable":
   Establishment, VIP, acclaimed, appalling, arrant, astonishing,
   baron, big, big boy, big bug, big cheese, big chief, big gun,
   big man, big name, big noise, big shot, big wheel,
   big-time operator, big-timer, bigwig, blatant, bold, brass,
   brass hat, celebrated, celebrity, character, chief, conspicuous,
   constellation, cynosure, czar, different, dignitary, dignity,
   distinctive, distinguished, egregious, elder, eminence, eminent,
   eminently, esteemed, estimable, exceedingly, exceptional,
   exceptionally, extraordinary, extremely, fabled, fabulous, famed,
   famous, fantastic, far-famed, far-heard, fat cat, father, figure,
   flagrant, folk hero, formidable, galaxy, glaring, great, great gun,
   great man, greatly, hanging out, heavyweight, hero, heroine,
   high-muck-a-muck, highly, his nibs, honored, hugely, idol,
   illustrious, immortal, important, important person, in relief,
   in the foreground, incredible, interests, king, leader, legendary,
   light, lion, lords of creation, luminaries, luminary, magnate,
   man of mark, marked, marvelous, master spirit, matchless,
   memorable, mogul, much acclaimed, mugwump, mythical, nabob, name,
   noble, notability, noted, noteworthy, noticeable, notorious,
   observable, obtrusive, of mark, of note, ostensible, outstanding,
   panjandrum, peerless, person of note, person of renown, personage,
   personality, pillar of society, pleiad, pop hero, popular,
   popular hero, popular idol, pot, power, power elite, prestigious,
   prince, prominent, pronounced, public figure, rare, recollectable,
   red-letter, remarkable, remarkably, rememberable, renowned,
   reputable, rubric, ruling circle, sachem, salient, signal,
   singular, social lion, somebody, something, special, star, staring,
   stark-staring, sticking out, striking, strikingly, superior,
   superstar, talked-about, talked-of, telling, the great, the top,
   top brass, top people, tycoon, uncommon, unforgettable, unmatched,
   unparalleled, unusual, very important person, well-known,
   wonderful, worthy