Goes under (5)
I believe the answer is:
sinks
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">goes under</span>' is the definition.<br/ ><span class="explanation-format__explanation">('sink' can be a synonym of 'go under')</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for sinks that I've seen before include "Scuttles" , "Basins" , "Dips" , "Goes down" , "Declines markedly" .)