Scornfully mocking (8)
I believe the answer is:
sardonic
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">scornfully mocking</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 sardonic that I've seen before include "Scornfully derisive" , "Dry, cynically mocking" , "Mocking or scornful" , "Scornfully mocking" , "Tart" .)