The Collaborative International Dictionary of English v.0.48:

Categorical \Cat`e*gor"ic*al\, a.
   1. Of or pertaining to a category.
      [1913 Webster]

   2. Not hypothetical or relative; admitting no conditions or
      exceptions; declarative; absolute; positive; express; as,
      a categorical proposition, or answer.
      [1913 Webster]

            The scriptures by a multitude of categorical and
            intelligible decisions . . . distinguish between the
            things seen and temporal and those that are unseen
            and eternal. --I. Taylor.
      [1913 Webster]

WordNet (r) 3.0 (2006):

categorical
    adj 1: relating to or included in a category or categories [syn:
           categorical, categoric]
    2: not modified or restricted by reservations; "a categorical
       denial"; "a flat refusal" [syn: categoric, categorical,
       flat, unconditional]

Moby Thesaurus II by Grady Ward, 1.0:

99 Moby Thesaurus words for "categorical":
   a fortiori, a posteriori, a priori, absolute,
   admitting no exception, all-out, analytic, apodeictic, apodictic,
   authoritative, certain, characteristic, classificational,
   classificatory, clean-cut, clear, clear-cut, complete, conclusive,
   conditional, decided, decisive, deductive, defining, definite,
   definitive, denominative, determinate, dialectic, differential,
   direct, discursive, distinctive, divisional, divisionary, dogmatic,
   downright, emphatic, enthymematic, entire, epagogic, explicit,
   express, final, firm, fixed, flat, flat-out, forthright, global,
   hypothetical, implicit, inappealable, indisputable, inductive,
   inferential, maieutic, ordinal, out-and-out, outright, particular,
   peculiar, peremptory, perfect, positive, round, soritical, special,
   specific, straight, straight-out, subdivisional, sure, syllogistic,
   synthetic, taxonomic, total, typal, typical, unambiguous,
   uncircumscribed, unconditional, unconditioned, undoubting,
   unequivocal, unhampered, unhesitating, unlimited, unmistakable,
   unmitigated, unqualified, unquestioning, unreserved, unrestricted,
   unwaivable, utter, whole, without exception, without reserve