17 across
In
drink,
lieutenant
is
very
loud
singer
(6)
In drink, lieutenant is very loud singer (6)
hints
0
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The definition is at the end of the clue.
How the clue works
The definition is singer — specifically someone who really belts one out. You've got BEER (your drink), and you slot LT (lieutenant) inside it to get BE-LT-ER, with the very loud bit being a red herring for the surface rather than contributing letters (LT does the work there as the abbreviation).