Leave gobsmacked
(Other definitions for stupefy that I've seen before include "Stun" , "Dumbfound" , "Astound" , "Astonish, shock" , "Knock out" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">leave gobsmacked</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 stun that I've seen before include "Daze with nuts" , "Daze, knock senseless" , "Put out for the count" , "Surprise greatly, knock someone''s socks off" , "Knock unconscious" .)