Source : Webster's Revised Unabridged Dictionary (1913)

Surprisal \Sur*pris"al\, n. [See {Surprise}, n.]
   The act of surprising, or state of being surprised; surprise.

         How to secure the lady from surprisal.   --Milton.

         Because death is uncertain, let us prevent its
         surprisal.                               --Barrow.

Source : WordNet®

surprisal
     n : the act of surprising someone [syn: {surprise}]