The Collaborative International Dictionary of English v.0.48:

Stupefaction \Stu`pe*fac"tion\, n. [Cf. F. stup['e]faction. See
   Stupefacient.]
   The act of stupefying, or the state of being stupefied.
   [Written also stupifaction.]
   [1913 Webster]

         Resistance of the dictates of conscience brings a
         hardness and stupefaction upon it.       --South.
   [1913 Webster]