Horrifies (6)
I believe the answer is:
appals
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">horrifies</span>' is the definition.<br/ ><span class="explanation-format__explanation">('appal' can be a synonym of 'horrify')</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for appals that I've seen before include "Fills with disgust" , "Fills with dismay or horror (6)" , "'Horrifies, outrages (6)'" , "Shocks" .)