Not strict enough (3)
I believe the answer is:
lax
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">not strict enough</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for lax that I've seen before include "Not sufficiently careful" , "Not taut" , "Loose, careless" , "Slapdash" , "Flabby" .)