The Collaborative International Dictionary of English v.0.48:

Illegitimate \Il`le*git"i*mate\, a.
   1. Not according to law; not regular or authorized; unlawful;
      improper.
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   2. Unlawfully begotten; born out of wedlock; bastard; as, an
      illegitimate child.
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   3. Not legitimately deduced or inferred; illogical; as, an
      illegitimate inference.
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   4. Not authorized by good usage; not genuine; spurious; as,
      an illegitimate word.
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   Illegitimate fertilization, or Illegitimate union (Bot.),
      the fertilization of pistils by stamens not of their own
      length, in heterogonously dimorphic and trimorphic
      flowers. --Darwin.
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