Undue speed (5)
I believe the answer is:
haste
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">undue speed</span>' is the definition.<br/ ><span class="explanation-format__explanation">(haste is hurrying or rushing)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for haste that I've seen before include "impetuosity" , "Inconsiderate speed" , "The more of it, the less speed sometimes" , "Heats (anag.)" , "''More . . . . ., less speed'' (5)" .)