Give in to gravity (3)
I believe the answer is:
sag
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">give in to gravity</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for sag that I've seen before include "Slump" , "Droop, flag" , "Lose energy" , "Sinking" , "Sink under weight" .)