Fetid (4)
I believe the answer is:
foul
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">fetid</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for foul that I've seen before include "Repulsive" , "Putrid" , "Violation of a sporting rule" , "Vile" , "Abhorrent" .)