Spoiling (7)
(Another definition for marring that I've seen is " Spoiling".)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">spoiling</span>' is the definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for indulgence that I've seen before include "leniency" , "Gratification, luxury" .)