ill-formed

from WordNet (r) 3.0 (2006)

ill-formed
    adj 1: not grammatical; not conforming to the rules of grammar
           or accepted usage [syn: {ungrammatical}, {ill-formed}]
           [ant: {grammatical}, {well-formed}]

from The Collaborative International Dictionary of English v.0.48

ill-formed \ill-formed\ adj.
   1. (Grammar) not grammatical; ungrammatical; not conforming
      to the rules of grammar or accepted usage. Opposite of
      {grammatical}.

   Syn: ungrammatical.
        [WordNet 1.5]

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