Invert (5)
I believe the answer is:
upend
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">invert</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 upend that I've seen before include "Tip right over" , "Turn on its head" , "Knock over" , "change things drastically" , "Trip" .)