Add measure of alcohol (3)

I believe the answer is:

tot

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'add' is the definition.
(synonyms)

'measure of alcohol' is the wordplay.
'measure' becomes 't' (T is an example).
'of alcohol' becomes 'ot' (I am not sure about this - if you are sure you should believe this answer much more).
't'+'ot'='TOT'

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(Other definitions for tot that I've seen before include "Small drink; accumulate" , "finger, possibly" , "Rum measure" , "Child's" , "Sum for the little one" .)

I've seen this clue in The Times.

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