Foul matter (5)
I believe the answer is:
filth
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">foul matter</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for filth that I've seen before include "Repulsive dirt" , "Squalor" , "Muck" , "Carrion" , "Real dirt or obscenity" .)