Source : Webster's Revised Unabridged Dictionary (1913)

Temerarious \Tem`er*a"ri*ous\, a. [L. temerarius. See
   {Temerity}.]
   Unreasonably adventurous; despising danger; rash; headstrong;
   audacious; reckless; heedless. -- {Tem`er*a"ri*ous*ly}, adv.

         I spake against temerarious judgment.    --Latimer.

Source : WordNet®

temerarious
     adj : presumptuously daring; "a daredevil test pilot having the
           right stuff" [syn: {brash}, {daredevil}]