Lawyer endlessly imbibing a liqueur (8)
I believe the answer is:
advocaat
'liqueur' is the definition.
(I know that Advocaat is a type of egg liqueur)
'lawyer endlessly imbibing a' is the wordplay.
'lawyer' becomes 'advocate' (advocate is a kind of lawyer).
'endlessly' means to remove the last letter.
'imbibing' indicates putting letters inside (drinking in).
'advocate' with its final letter removed is 'advocat'.
'advocat' enclosing 'a' is 'ADVOCAAT'.
(Other definitions for advocaat that I've seen before include "Egg-based liqueur" , "medicinal drink" , "Liqueur made with raw eggs" , "Liqueur containing raw eggs" , "Liqueur made from eggs, sugar and brandy" .)