The Collaborative International Dictionary of English v.0.48:

Estimable \Es"ti*ma*ble\, a. [F. estimable, or L. aestimabilis.
   See Esteem.]
   1. Capable of being estimated or valued; as, estimable
      damage. --Paley. .
      [1913 Webster]

   2. Valuable; worth a great price. [R.]
      [1913 Webster]

            A pound of man's flesh, taken from a man,
            Is not so estimable, profitable neither,
            As flesh of muttons, beefs, or goats. --Shak.
      [1913 Webster]

   3. Worth of esteem or respect; deserving our good opinion or
      regard.
      [1913 Webster]

            A lady said of her two companions, that one was more
            amiable, the other more estimable.    --Sir W.
                                                  Temple.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Estimable \Es"ti*ma*ble\, n.
   A thing worthy of regard. [R.]
   [1913 Webster]

         One of the peculiar estimables of her country. --Sir T.
                                                  Browne.
   [1913 Webster]

WordNet (r) 3.0 (2006):

estimable
    adj 1: deserving of respect or high regard [ant: contemptible]
    2: deserving of esteem and respect; "all respectable companies
       give guarantees"; "ruined the family's good name" [syn:
       estimable, good, honorable, respectable]
    3: may be computed or estimated; "a calculable risk";
       "computable odds"; "estimable assets" [syn: computable,
       estimable]

Moby Thesaurus II by Grady Ward, 1.0:

188 Moby Thesaurus words for "estimable":
   Christian, admirable, admired, advantageous, appraisable,
   appreciable, assessable, august, auspicious, authoritative,
   awe-inspiring, awesome, awful, beneficial, benevolent,
   beyond all praise, blameless, bon, bonny, braw, bueno, calculable,
   capital, celebrated, charismatic, charming, clean, cogent,
   commendable, computable, consequential, conspicuous, countable,
   creditable, decent, deserving, determinable, distinguished,
   dreadful, effective, effectual, efficacious, elegant, eminent,
   enchanting, erect, esteemed, ethical, excellent, exceptional,
   exemplary, expedient, extraordinary, fair, famous, fathomable,
   favorable, fine, full of integrity, gaugeable, good, goodly, grand,
   healthy, held in esteem, helpful, high-minded, high-principled,
   highly esteemed, highly regarded, highly reputed,
   highly respectable, honest, honorable, honored, immaculate,
   important, in favor, in good odor, in high favor, influential,
   inviolate, irreproachable, just, kind, laudable, law-abiding,
   law-loving, law-revering, magnetic, manly, marked, measurable,
   memorable, mensurable, meritorious, meterable, model, momentous,
   moral, nice, noble, notable, noteworthy, noticeable, numberable,
   numerable, of mark, outstanding, perceptible, personable,
   persuasive, pleasant, potent, powerful, praiseworthy, prestigious,
   principled, profitable, prominent, pure, quantifiable, quantizable,
   rare, reckonable, regal, remarkable, rememberable, reputable,
   reputed, respectable, respected, revered, reverend, right,
   right-minded, righteous, royal, salient, signal, skillful, sound,
   special, splendid, spotless, stainless, sterling, striking, strong,
   suasive, substantial, telling, time-honored, true-dealing,
   true-devoted, true-disposing, true-souled, true-spirited,
   truehearted, unblemished, uncorrupt, uncorrupted, undefiled,
   unexceptionable, unforgettable, unimpeachable, unspotted,
   unstained, unsullied, untarnished, upright, uprighteous,
   upstanding, useful, valid, valuable, valued, venerable, venerated,
   very good, virtuous, weighty, well-deserving, well-thought-of,
   winning, worshipful, worthy, yeomanly