Aspersion (4)
I believe the answer is:
slur
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">aspersion</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for slur that I've seen before include "Slight - incoherence in speech" , "making indistinct sound" , "Disparage" , "Negative comment" , "Slight - drawl" .)