Destructive wave (7)
I believe the answer is:
tsunami
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">destructive wave</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for tsunami that I've seen before include "stormy sea" , "crashing bore" , "Freak wave" , "Huge destructive sea wave" , "Large tidal wave" .)