Sacred or inviolable (10)
I believe the answer is:
sacrosanct
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">sacred</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ >'<span class="explanation-format__original">inviolable</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that inviolable can be written as sacrosanct)</span><br/ ><br/ ></span>
(Other definitions for sacrosanct that I've seen before include "Too important to touch" , "Inviolable" , "above criticism" , "Unchallengeable" , "protected" .)