Hard to undo; drunk (5)
I believe the answer is:
tight
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">hard to undo</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >'<span class="explanation-format__original">drunk</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(slang term)</span><br/ ><br/ ></span>
(Other definitions for tight that I've seen before include "Strictly imposed; drunk" , "Miserly (informal) - drunk (informal)" , "Difficult and problematic" , "Mean - drunk" , "Close-fitting; tense" .)