Depart quickly (9)
I believe the answer is:
skedaddle
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">depart quickly</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 skedaddle that I've seen before include "run away" , "Scram" , "Quickly get out" , "take flight" , "Depart quickly (colloq.)" .)