Foul odour (6)
I believe the answer is:
stench
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">foul odour</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for stench that I've seen before include "Strong offensive smell" , "Miasma" , "smell, to put it mildly" , "A really foul smell" , "Awful pong" .)