Source : Webster's Revised Unabridged Dictionary (1913)

Stressful \Stress"ful\, a.
   Having much stress. --Rush.

Source : WordNet®

stressful
     adj : extremely irritating to the nerves; "nerve-racking noise";
           "the stressful days before a war"; "a trying day at the
           office" [syn: {nerve-racking}, {nerve-wracking}, {trying}]