Cask, keg (6)
I believe the answer is:
barrel
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">cask</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >'<span class="explanation-format__original">keg</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ ></span>
(Other definitions for barrel that I've seen before include "Large keg" , "Tube of a gun" , "Cheerful old song: 'Roll out the . . . . . .'" , "Revolving drum" , "full of laughs?" .)