The Collaborative International Dictionary of English v.0.48:

Unexceptionable \Unexceptionable\
   See exceptionable.

The Collaborative International Dictionary of English v.0.48:

Unexceptionable \Un`ex*cep"tion*a*ble\, a.
   Not liable to any exception or objection; unobjectionable;
   faultless; good; excellent; as, a man of most unexceptionable
   character. -- Un`ex*cep"tion*a*ble*ness, n. --
   Un`ex*cep"tion*a*bly, adv.
   [1913 Webster]
   [1913 Webster]

         Chesterfield is an unexceptionable witness. --Macaulay.
   [1913 Webster]

WordNet (r) 3.0 (2006):

unexceptionable
    adj 1: completely acceptable; not open to exception or reproach;
           "two unexceptionable witnesses"; "a judge's ethics should
           be unexceptionable" [syn: unexceptionable,
           unimpeachable]

Moby Thesaurus II by Grady Ward, 1.0:

68 Moby Thesaurus words for "unexceptionable":
   OK, above suspicion, acceptable, adequate, admirable, admissible,
   agreeable, all right, alright, believable, better than nothing,
   beyond all praise, colorable, commendable, common, conceivable,
   credible, creditable, decent, deserving, estimable, exemplary,
   fair, fairish, fiduciary, good enough, goodish, inculpable,
   irreprehensible, irreproachable, irreprovable, laudable,
   meritorious, model, moderate, not amiss, not bad, not half bad,
   not so bad, okay, passable, plausible, praiseworthy, presentable,
   pretty good, reliable, respectable, satisfactory, sufficient,
   tenable, tidy, tolerable, trustworthy, trusty, unarraignable,
   unblamable, unblameworthy, uncensurable, unexceptional,
   unimpeachable, unindictable, unobjectionable, unquestionable,
   viable, well-deserving, workmanlike, worthy, worthy of faith