Dived (7)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">dived</span>' is the definition.<br/ ><span class="explanation-format__explanation">('plunge' can be a synonym of 'dive')</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for plunged that I've seen before include "Immersed" , "Dived" , "Dove in US" .)
(Another definition for swooped that I've seen is " Came down quickly".)