Source : Webster's Revised Unabridged Dictionary (1913)

Audacious \Au*da"cious\, a. [F. audacieux, as if fr. LL.
   audaciosus (not found), fr. L. audacia audacity, fr. audax,
   -acis, bold, fr. audere to dare.]
   1. Daring; spirited; adventurous.

            As in a cloudy chair, ascending rides Audacious.
                                                  --Milton.

   2. Contemning the restraints of law, religion, or decorum;
      bold in wickedness; presumptuous; impudent; insolent. ``
      Audacious traitor.'' --Shak. `` Such audacious
      neighborhood.'' --Milton.

   3. Committed with, or proceedings from, daring effrontery or
      contempt of law, morality, or decorum. ``Audacious
      cruelty.'' ``Audacious prate.'' --Shak.

Source : WordNet®

audacious
     adj 1: invulnerable to fear or intimidation; "audacious explorers";
            "fearless reporters and photographers"; "intrepid
            pioneers" [syn: {brave}, {dauntless}, {fearless}, {intrepid},
             {unfearing}]
     2: unrestrained by convention or propriety; "an audacious trick
        to pull"; "a barefaced hypocrite"; "the most bodacious
        display of tourism this side of Anaheim"- Los Angeles
        Times; "bold-faced lies"; "brazen arrogance"; "the modern
        world with its quick material successes and insolent
        belief in the boundless possibilities of progress"-
        Bertrand Russell [syn: {barefaced}, {bodacious}, {bold-faced},
         {brassy}, {brazen}, {brazen-faced}, {insolent}]
     3: disposed to venture or take risks; "audacious visions of the
        total conquest of space"; "an audacious interpretation of
        two Jacobean dramas"; "the most daring of contemporary
        fiction writers"; "a venturesome investor"; "a venturous
        spirit" [syn: {daring}, {venturesome}, {venturous}]