Enormous wave (7)
I believe the answer is:
tsunami
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">enormous 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 "Freak wave" , "Large ocean wave" , "Destructive tidal wave" , "crashing bore" , "Large sea wave caused by an earthquake" .)