challenging

challenging
    adj 1: requiring full use of your abilities or resources;
           "ambitious schedule"; "performed the most challenging
           task without a mistake" [syn: {ambitious}, {challenging}]
    2: stimulating interest or thought; "a challenging hypothesis";
       "a thought-provoking book" [syn: {challenging}, {thought-
       provoking}]
    3: disturbingly provocative; "an intriguing smile" [syn:
       {challenging}, {intriguing}]
    

Challenge \Chal"lenge\, v. t. [imp. & p. p. {Challenged}; p. pr.
   & vb. n. {Challenging}.] [OE. chalengen to accuse, claim, OF.
   chalengier, chalongier, to claim, accuse, dispute, fr. L.
   calumniar to attack with false accusations. See {Challenge},
   n., and cf. {Calumniate}.]
   1. To call to a contest of any kind; to call to answer; to
      defy.
      [1913 Webster]

            I challenge any man to make any pretense to power by
            right of fatherhood.                  --Locke.
      [1913 Webster]

   2. To call, invite, or summon to answer for an offense by
      personal combat.
      [1913 Webster]

            By this I challenge him to single fight. --Shak.
      [1913 Webster]

   3. To claim as due; to demand as a right.
      [1913 Webster]

            Challenge better terms.               --Addison.
      [1913 Webster]

   4. To censure; to blame. [Obs.]
      [1913 Webster]

            He complained of the emperors . . . and challenged
            them for that he had no greater revenues . . . from
            them.                                 --Holland.
      [1913 Webster]

   5. (Mil.) To question or demand the countersign from (one who
      attempts to pass the lines); as, the sentinel challenged
      us, with "Who comes there?"
      [1913 Webster]

   6. To take exception to; question; as, to challenge the
      accuracy of a statement or of a quotation.
      [1913 Webster]

   7. (Law) To object to or take exception to, as to a juror, or
      member of a court.
      [1913 Webster]

   8. To object to the reception of the vote of, as on the
      ground that the person in not qualified as a voter. [U.
      S.]
      [1913 Webster]

   {To challenge to the} {array, favor, polls}. See under
      {Challenge}, n.
      [1913 Webster]
    

challenging \challenging\ adj.
   1. requiring full use of one's abilities or resources; as,
      challenging task.

   Syn: ambitious, demanding.
        [WordNet 1.5]

   2. disposed to or engaged in defiance of established
      authority.

   Syn: insubordinate, resistant, resistive.
        [WordNet 1.5]
    

39 Moby Thesaurus words for "challenging":
      alluring, arrogant, audacious, bold, brash, brassy, brazen,
      bumptious, cheeky, cocky, contemptuous, daring, defiant, defying,
      derisive, disdainful, disregardful, encouraging, energizing,
      exciting, galvanic, galvanizing, greatly daring, impertinent,
      impudent, insolent, inviting, pert, piquant, prompting,
      provocative, provoking, regardless of consequences, rousing, saucy,
      stimulant, stimulating, stimulative, stirring