Overly eager speed (5)
I believe the answer is:
haste
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">overly eager speed</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 haste that I've seen before include "Inconsiderate speed" , "Promptitude" , "Leader abandons modest" , "Possible cause of careless mistakes?" , "Over-eager speed" .)