The Collaborative International Dictionary of English v.0.48:

Peremptory \Per"emp*to*ry\, a. [L. peremptorius destructive,
   deadly, decisive, final: cf. F. p['e]remptorie. See
   Perempt.]
   1. Precluding debate or expostulation; not admitting of
      question or appeal; positive; absolute; decisive;
      conclusive; final.
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            Think of heaven with hearty purposes and peremptory
            designs to get thither.               --Jer. Taylor.
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   2. Positive in opinion or judgment; decided; dictatorial;
      dogmatical.
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            Be not too positive and peremptory.   --Bacon.
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            Briefly, then, for we are peremptory. --Shak.
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   3. Firmly determined; unawed. [Poetic] --Shak.
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   Peremptory challenge (Law) See under Challenge.

   Peremptory mandamus, a final and absolute mandamus.

   Peremptory plea, a plea by a defendant tending to impeach
      the plaintiff's right of action; a plea in bar.
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   Syn: Decisive; positive; absolute; authoritative; express;
        arbitrary; dogmatical.
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The Collaborative International Dictionary of English v.0.48:

Challenge \Chal"lenge\, n. [OE. chalenge claim, accusation,
   challenge, OF. chalenge, chalonge, claim, accusation,
   contest, fr. L. calumnia false accusation, chicanery. See
   Calumny.]
   1. An invitation to engage in a contest or controversy of any
      kind; a defiance; specifically, a summons to fight a duel;
      also, the letter or message conveying the summons.
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            A challenge to controversy.           --Goldsmith.
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   2. The act of a sentry in halting any one who appears at his
      post, and demanding the countersign.
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   3. A claim or demand. [Obs.]
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            There must be no challenge of superiority.
                                                  --Collier.
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   4. (Hunting) The opening and crying of hounds at first
      finding the scent of their game.
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   5. (Law) An exception to a juror or to a member of a court
      martial, coupled with a demand that he should be held
      incompetent to act; the claim of a party that a certain
      person or persons shall not sit in trial upon him or his
      cause. --Blackstone
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   6. An exception to a person as not legally qualified to vote.
      The challenge must be made when the ballot is offered. [U.
      S.]
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   Challenge to the array (Law), an exception to the whole
      panel.

   Challenge to the favor, the alleging a special cause, the
      sufficiency of which is to be left to those whose duty and
      office it is to decide upon it.

   Challenge to the polls, an exception taken to any one or
      more of the individual jurors returned.

   Peremptory challenge, a privilege sometimes allowed to
      defendants, of challenging a certain number of jurors
      (fixed by statute in different States) without assigning
      any cause.

   Principal challenge, that which the law allows to be
      sufficient if found to be true.
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