Tom Collins liquor (3)
I believe the answer is:
gin
'tom collins liquor' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for gin that I've seen before include "Trap for snaring small mammals" , "Juniper-flavoured drink" , "Colourless spirit flavoured with juniper berries - mother's ruin" , "Alcoholic drink once known as mother's ruin" , "Machine for separating cotton from its seeds" .)