Busy, busy (2,3,2)
I believe the answer is:
on the go
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">busy busy</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for on the go that I've seen before include "Running around busily" , "Very active (colloq.)" , "Active, always doing something" , "Active and energetic" , "Busily active" .)