Central characters in novel about Colditz liked a drink (5)

I believe the answer is:

vodka

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'drink' is the definition.
(I know that vodka is a drink)

I don't understand the remainder of the clue.

(Other definitions for vodka that I've seen before include "Strong drink" , "Spirit used in a Bloody Mary" , "Alcoholic spirit of Russian origin" , "Russian tipple" , "Colourless alcohol" .)

I've seen this clue in The Independent.

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