Rapid surprise attack (4)
I believe the answer is:
raid
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">rapid surprise attack</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for raid that I've seen before include "Enter a territory and take spoils" , "Sudden short attack" , "A sudden military attack and withdrawal" , "Sally" , "Inroad" .)