Judders (6)
I believe the answer is:
shakes
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">judders</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know this)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for shakes that I've seen before include "Moves quickly up and down, say milk drink" , "jars" , "Quivers" , "Judders" , "Frothy drink of milk and flavouring" .)