Vanishes (10)
I think it could be either:
drops out of sight
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">vanishes</span>' is the definition.<br/ ><span class="explanation-format__explanation">('disappear' can be a synonym of 'vanish')</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for disappears that I've seen before include "goes missing" , "becomes lost" .)