Heavy fall of rain (8)
I believe the answer is:
downpour
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">heavy fall of rain</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 downpour that I've seen before include "falling water" , "Heavy continuous rainfall" , "Heavy shower" , "Deluge" , "Big fall makes" .)