Source : Webster's Revised Unabridged Dictionary (1913)

Stupefy \Stu"pe*fy\, v. t. [imp. & p. p. {Stupefied}; p. pr. &
   vb. n. {Stupefying}.] [F. stup['e]fier, fr. L. stupere to be
   stupefied + ficare (in comp.) to make, akin to facere. See
   {Stupid}, {Fact}, and cf. {Stupefacient}.] [Written also
   {stupify}, especially in England.]
   1. To make stupid; to make dull; to blunt the faculty of
      perception or understanding in; to deprive of sensibility;
      to make torpid.

Source : WordNet®

stupefying
     adj 1: so surprisingly impressive as to stun or overwhelm; "such an
            enormous response was astonishing"; "an astounding
            achievement"; "the amount of money required was
            staggering"; "suffered a staggering defeat"; "the
            figure inside the boucle dress was stupefying" [syn: {astonishing},
             {astounding}, {staggering}]
     2: making physically stupid or dull or insensible; "a
        stupefying blow to the head"; "the stupefying effects of
        hemp"
     3: shocking with surprise and consternation; "the stupefying
        impact of the tragedy"