Source : Webster's Revised Unabridged Dictionary (1913)

Hazardous \Haz"ard*ous\, a. [Cf. F. hasardeux.]
   Exposed to hazard; dangerous; risky.

         To enterprise so hazardous and high!     --Milton.

   Syn: Perilous; dangerous; bold; daring; adventurous;
        venturesome; precarious; uncertain. -- {Haz"ard*ous*ly},
        adv. -- {Haz"ard*ous*ness}, n.

Source : WordNet®

hazardous
     adj : involving risk or danger; "skydiving is a hazardous sport";
           "extremely risky going out in the tide and fog"; "a
           venturesome journey in wintertime"; "a venturous
           enterprise" [syn: {risky}, {venturesome}, {venturous}]