The Collaborative International Dictionary of English v.0.48:

Substantive \Sub"stan*tive\, a. [L. substantivus: cf. F.
   substantif.]
   1. Betokening or expressing existence; as, the substantive
      verb, that is, the verb to be.
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   2. Depending on itself; independent.
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            He considered how sufficient and substantive this
            land was to maintain itself without any aid of the
            foreigner.                            --Bacon.
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   3. Enduring; solid; firm; substantial.
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            Strength and magnitude are qualities which impress
            the imagination in a powerful and substantive
            manner.                               --Hazlitt.
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   4. Pertaining to, or constituting, the essential part or
      principles; as, the law substantive.
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   Noun substantive (Gram.), a noun which designates an
      object, material or immaterial; a substantive.

   Substantive color, one which communicates its color without
      the aid of a mordant or base; -- opposed to adjective
      color.
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The Collaborative International Dictionary of English v.0.48:

Substantive \Sub"stan*tive\, n. [Cf. F. substantif.] (Gram.)
   A noun or name; the part of speech which designates something
   that exists, or some object of thought, either material or
   immaterial; as, the words man, horse, city, goodness,
   excellence, are substantives.
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The Collaborative International Dictionary of English v.0.48:

Substantive \Sub"stan*tive\, v. t.
   To substantivize. [R.] --Cudworth.
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WordNet (r) 3.0 (2006):

substantive
    adj 1: having a firm basis in reality and being therefore
           important, meaningful, or considerable; "substantial
           equivalents" [syn: substantial, substantive]
    2: defining rights and duties as opposed to giving the rules by
       which rights and duties are established; "substantive law"
       [syn: substantive, essential] [ant: adjective,
       procedural]
    3: being on topic and prompting thought; "a meaty discussion"
       [syn: meaty, substantive]
    n 1: any word or group of words functioning as a noun

Moby Thesaurus II by Grady Ward, 1.0:

68 Moby Thesaurus words for "substantive":
   ab ovo, abstract noun, adherent noun, adjectival, adverbial,
   appreciable, attributive, basal, basic, bedrock, central,
   collective noun, common noun, concrete, conjunctive, constituent,
   constitutive, copulative, correct, elemental, elementary,
   essential, focal, formal, functional, fundamental, gerund,
   glossematic, grammatic, gut, hypostasis, indispensable,
   intransitive, life-and-death, life-or-death, linking, material,
   nominal, noun, noun phrase, of the essence, of vital importance,
   original, palpable, participial, ponderable, postpositional,
   prepositional, primal, primary, primitive, pronominal, pronoun,
   proper noun, quotation noun, radical, real, sensible, solid,
   structural, substantial, syntactic, tagmemic, tangible, transitive,
   underlying, verbal, vital