Horrified (6)
I believe the answer is:
aghast
'horrified' is the definition.
(I know that horrified can be written as aghast)
This is the entire clue.
(Other definitions for aghast that I've seen before include "Horror-struck" , "in awe" , "Filled with terror" , "Stupefied with horrer" , "Filled with horror or shock" .)