Flood, downpour (6)
I believe the answer is:
deluge
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">flood</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that deluge is a more specific form of flood)</span><br/ ><br/ >'<span class="explanation-format__original">downpour</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that downpour can be written as deluge)</span><br/ ><br/ ></span>
(Other definitions for deluge that I've seen before include "Overwhelm with water" , "Severe flood" , "A heavy downpour of rain" , "Inundation" , "Cloudburst, downpour" .)