Mark of disgrace (6)
I believe the answer is:
stigma
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">mark of disgrace</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for stigma that I've seen before include "Mark of shame or social disgrace" , "Part of a flower" , "Mark of infamy or disgrace" , "Mark of shame, stain on reputation" , "Bad mark" .)