Dash, run quickly (6)
I believe the answer is:
sprint
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">dash</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >'<span class="explanation-format__original">run quickly</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ ></span>
(Other definitions for sprint that I've seen before include "Run at full speed for a short distance" , "quick run" , "Run quickly" , "Short fast run" , "To make fast progress" .)