Source : Webster's Revised Unabridged Dictionary (1913)

Startle \Star"tle\, v. t. [imp. & p. p. {Startled}; p. pr. & vb.
   n. {Startling}.] [Freq. of start.]
   To move suddenly, or be excited, on feeling alarm; to start.

         Why shrinks the soul Back on herself, and startles at
         destruction?                             --Addison.

Source : WordNet®

startled
     adj : excited by sudden surprise or alarm and making a quick
           involuntary movement; "students startled by the
           teacher's quiet return"; "the sudden fluttering of the
           startled pigeons"; "her startled expression"