Squirm, twist (6)
I believe the answer is:
writhe
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">squirm</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >'<span class="explanation-format__original">twist</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ ></span>
(Other definitions for writhe that I've seen before include "Squirm in pain" , "'Twist, squirm (6)'" , "6, maybe in agony" , "Twist as in pain" , "Struggle" .)