Rotational force (6)
I believe the answer is:
torque
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">rotational force</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for torque that I've seen before include "Source of spin" , "Quoter (anag.)" , "Rotational force; roquet (anag.)" , "Turning force" , "Rotating forces" .)