Wordnet 3.0
ADJECTIVE (2)
1. 
 precise; 
 explicit and clearly defined; 
- Example: "I want a definite answer"- Example: "a definite statement of the terms of the will"- Example: "a definite amount"- Example: "definite restrictions on the sale of alcohol"- Example: "the wedding date is now definite"- Example: "a definite drop in attendance"2. 
 known for certain; 
- Example: "it is definite that they have won"
The Collaborative International Dictionary of English v.0.48:
Definite \Def"i*nite\, a. [L. definitis, p. p. of definire: cf.
   F. d['e]fini. See Define.]
   1. Having certain or distinct; determinate in extent or
      greatness; limited; fixed; as, definite dimensions; a
      definite measure; a definite period or interval.
      [1913 Webster]
            Elements combine in definite proportions. --Whewell.
      [1913 Webster]
   2. Having certain limits in signification; determinate;
      certain; precise; fixed; exact; clear; as, a definite
      word, term, or expression.
      [1913 Webster]
   3. Determined; resolved. [Obs.] --Shak.
      [1913 Webster]
   4. Serving to define or restrict; limiting; determining; as,
      the definite article.
      [1913 Webster]
   Definite article (Gram.), the article the, which is used to
      designate a particular person or thing, or a particular
      class of persons or things; -- also called a definitive.
      See Definitive, n. -
   Definite inflorescence. (Bot.) See Determinate
      inflorescence, under Determinate.
   Law of definite proportions (Chem.), the essential law of
      chemical combination that every definite compound always
      contains the same elements in the same proportions by
      weight; and, if two or more elements form more than one
      compound with each other, the relative proportions of each
      are fixed. Compare Law of multiple proportions, under
      Multiple.
      [1913 Webster]
The Collaborative International Dictionary of English v.0.48:
Definite \Def"i*nite\, n.
   A thing defined or determined. [Obs.]
   [1913 Webster]
WordNet (r) 3.0 (2006):
definite
    adj 1: precise; explicit and clearly defined; "I want a definite
           answer"; "a definite statement of the terms of the will";
           "a definite amount"; "definite restrictions on the sale
           of alcohol"; "the wedding date is now definite"; "a
           definite drop in attendance" [ant: indefinite]
    2: known for certain; "it is definite that they have won"
Moby Thesaurus II by Grady Ward, 1.0:
175 Moby Thesaurus words for "definite":
   absolute, admitting no exception, all-out, apodictic, articulate,
   assigned, assured, audible, bound, bound and determined,
   categorical, certain, circumscribed, circumscript, clean-cut,
   clear, clear and distinct, clear as crystal, clear as day,
   clear-cut, coherent, committed, complete, conclusive, concrete,
   confirmed, connected, consistent, conspicuous, contrastive, crisp,
   crystal-clear, crystalline, decided, decisive, dedicated, defined,
   definitive, delimited, demarcated, detailed, determinate,
   determined, devoted, different, direct, distinct, distinctive,
   distinguished, downright, earnest, encircled, entire, esoteric,
   especial, established, evident, exact, exceptional, explicit,
   express, extraordinary, final, fixed, flat, flat-out, forthright,
   full, glaring, global, hearable, hedged about, hi-fi,
   high-fidelity, implicit, in focus, inappealable, incisive,
   indisputable, individual, ineluctable, inevitable, inner, intimate,
   limited, limpid, loud and clear, lucid, luminous, minute, narrow,
   necessary, noteworthy, obstinate, obvious, out-and-out, outright,
   particular, patent, pellucid, peremptory, perfect, perfectly sure,
   persevering, persistent, personal, perspicuous, plain, positive,
   precise, predestined, predetermined, prescribed, private,
   prominent, pronounced, purposeful, relentless, resolute, resolved,
   respective, restricted, round, serious, set, settled, several,
   simple, sincere, single-minded, singular, solipsistic, special,
   specific, staring, stated, straight, straight-out, straightforward,
   sure, sure-enough, surrounded, tenacious, total, translucent,
   transparent, transpicuous, true, unambiguous, uncircumscribed,
   unconditional, unconditioned, unconfused, undoubting, unequivocal,
   unhampered, unhesitating, univocal, unlimited, unmistakable,
   unmitigated, unqualified, unquestioning, unreserved, unrestricted,
   unwaivable, utter, well-defined, well-marked, well-pronounced,
   well-resolved, whole, wholehearted, without exception,
   without reserve