Horrible smell (6)
I believe the answer is:
stench
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">horrible smell</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 stench that I've seen before include "Reek" , "A really bad smell" , "Miasma" , "Hum" , "Strong offensive smell" .)