Not tight (5)
I believe the answer is:
loose
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">not tight</span>' is the definition.<br/ ><span class="explanation-format__explanation">('loose' is the opposite to 'tight')</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for loose that I've seen before include "released from confinement" , "Unfettered" , "Liberal" , "Unrestricted" , "Not tied up or attached" .)