Add a little whisky, perhaps (3)

I believe the answer is:

tot

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'add' is the definition.
(synonyms)

I cannot understand how the rest of the clue works.

(Other definitions for tot that I've seen before include "Add up like infant" , "A wee dram" , "Sum for the little one" , "Child's" , "nipper" .)

I've seen this clue in The Times.

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