The Collaborative International Dictionary of English v.0.48:

Ghast \Ghast\, v. t. [OE. gasten. See Ghastly, a.]
   To strike aghast; to affright. [Obs.]
   [1913 Webster]

         Ghasted by the noise I made.
         Full suddenly he fled.                   --Shak.
   [1913 Webster]