Not at all drunk (5,4,5)
I believe the answer is:
stone cold sober
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">not at all drunk</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for stone cold sober that I've seen before include "on the wagon" , "off the booze" .)