Martini component (3)
I believe the answer is:
gin
'martini component' 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 "Juniper-flavoured spirit" , "Trap for snaring small mammals" , "Spirit, aka 'Mother's ruin'" , "Alcohol made with juniper berries" , "Liquor flavoured with juniper berries" .)