Whiskey barrel (4)
I believe the answer is:
cask
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">whiskey barrel</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that whiskey barrel can be written as cask)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for cask that I've seen before include "Large barrel" , "Cylinder for liquid" , "Wine barrel" , "VAT?" , "Measure" .)