Not on the rocks (4)
I believe the answer is:
neat
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">not on the rocks</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for neat that I've seen before include "without water being added" , "Tidy and uncluttered" , "Steers" , "Drink with no water added" , "Tidy - undiluted" .)