Martini ingredient (3)
'martini ingredient' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for gin that I've seen before include "Alcohol made with juniper berries" , "Common spirit" , "Spirit; trap" , "Alcohol for the snare" , "Trap for snaring small mammals" .)
(Other definitions for vermouth that I've seen before include "Flavoured wine often mixed with gin" , "It, possibly" , "Flavoured wine used in cocktails" , "Herb-flavoured wine drunk with gin" , "it in the bar" .)