Energetic activity (6)
I believe the answer is:
bustle
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">energetic activity</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 bustle that I've seen before include "Energetic activity" , "Hurried activity - old padded support for woman's dress" , "Hurried and noisy activity" , "Excited activity of subtle kind" , "Busy activity; old skirt padding" .)