Horrible, revolting (6)
I believe the answer is:
grisly
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">horrible</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >'<span class="explanation-format__original">revolting</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ ></span>
(Other definitions for grisly that I've seen before include "Causing horror or disgust" , "Horrible, ghastly" , "Causing horror or revulsion" , "Horrific" , "Very unpleasant" .)