Grammatical

from WordNet (r) 3.0 (2006)

grammatical
    adj 1: of or pertaining to grammar; "the grammatic structure of
           a sentence"; "grammatical rules"; "grammatical gender"
           [syn: {grammatical}, {grammatic}]
    2: conforming to the rules of grammar or usage accepted by
       native speakers; "spoke in grammatical sentences" [syn:
       {grammatical}, {well-formed}] [ant: {ill-formed},
       {ungrammatical}]

from The Collaborative International Dictionary of English v.0.48

Grammatical \Gram*mat"ic*al\, a. [L. grammaticus, grammaticalis;
   Gr. ? skilled in grammar, knowing one's letters, from ? a
   letter: cf. F. grammatical. See {Grammar}.]
   1. Of or pertaining to grammar; of the nature of grammar; as,
      a grammatical rule.
      [1913 Webster]

   2. According to the rules of grammar; grammatically correct;
      as, the sentence is not grammatical; the construction is
      not grammatical. --{Gram*mat"ic*al*ly}, adv. --
      {Gram*mat"ic*al*ness}, n.
      [1913 Webster]

from Moby Thesaurus II by Grady Ward, 1.0

40 Moby Thesaurus words for "grammatical":
      adjectival, adverbial, attributive, conjunctive, copulative,
      correct, descriptive, formal, functional, glossematic,
      glottochronological, grammatic, graphemic, intransitive,
      lexicographic, lexicological, lexicostatistical, lingual,
      linguistic, linking, metalinguistic, morphological, morphophonemic,
      nominal, participial, philological, phonemic, phonetic,
      phonological, postpositional, prepositional, pronominal,
      psycholinguistic, semantic, structural, substantive, syntactic,
      tagmemic, transitive, verbal