Cocktail made by male wearing waistcoat (6)
I believe the answer is:
gimlet
'cocktail' is the definition.
(I know that gimlet is a type of cocktail)
'male wearing waistcoat' is the wordplay.
'male' becomes 'm' (common abbreviation).
'wearing' means one lot of letters goes inside another.
'waistcoat' becomes 'gilet' (I've seen this before).
'm' going within 'gilet' is 'GIMLET'.
'made by' is the link.
(Other definitions for gimlet that I've seen before include "Tool for boring holes and a cocktail" , "Cocktail of gin, or sometimes vodka, and lime juice" , "Wood-boring tool" , "a boring thing" , "Small hand tool - cocktail of vodka or gin with lime juice" .)