Taint, sully (8)
I believe the answer is:
besmirch
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">taint</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ >'<span class="explanation-format__original">sully</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that sully can be written as besmirch)</span><br/ ><br/ ></span>
(Other definitions for besmirch that I've seen before include "Foul" , "Damage (a reputation)" , "run down" , "soil" , "Sully" .)