The Collaborative International Dictionary of English v.0.48:

Horrify \Hor"ri*fy\, v. t. [imp. & p. p. Horrified; p. pr. &
   vb. n. Horrifying.] [L. horrificare. See Horrific.]
   To cause to feel horror; to strike or impress with horror;
   as, the sight horrified the beholders. --E. Irving.
   [1913 Webster]

WordNet (r) 3.0 (2006):

horrified
    adj 1: stricken with horror [syn: horrified, horror-
           stricken, horror-struck]