Drink in large draughts (5)
I believe the answer is:
quaff
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">drink in large draughts</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for quaff that I've seen before include "Knock back" , "Imbibe" , "Drink deeply or eagerly" , "Drink enthusiastically" , "Drink in large draughts" .)