It may be used for boring cocktail (6)
I believe the answer is:
gimlet
'cocktail' is the definition.
(I know that Gimlet is a type of cocktail)
I don't understand the remainder of the clue.
(Other definitions for gimlet that I've seen before include "Boring tool; US cocktail" , "Hole borer" , "One pierces" , "A carpenter's tool" , "Something for boring; cocktail" .)