Sneering (5)
I believe the answer is:
snide
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">sneering</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for snide that I've seen before include "Derogatory in an insinuating way" , "Unpleasantly mocking" , "Delivering cuts" , "Dines (anag.)" , "Sarcastic" .)