Running (6)
I believe the answer is:
racing
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">running</span>' is the definition.<br/ ><span class="explanation-format__explanation">('race' can be a synonym of 'run')</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for racing that I've seen before include "Competing in speed contest" , "activity on track" , "Competing in a speed competition" , "Dashing" , "Running fast" .)