Plummeted; hill (4)
I believe the answer is:
fell
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">plummeted</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >'<span class="explanation-format__original">hill</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ ></span>
(Other definitions for fell that I've seen before include "High moorland or unforested hill in the UK" , "lambs > went down > hill" , "animal skin" , "Chop down" , "Mountain - lost footing - deadly" .)