Fix a drink, getting US lawyer a cocktail (4,6)
I believe the answer is:
pina colada
'a cocktail' is the definition.
(I've seen this before)
'fix a drink getting us lawyer' is the wordplay.
'fix' becomes 'pin' (to pin is to fix in place).
'drink' becomes 'cola' (cola is a type of drink).
'getting' means one lot of letters go next to another.
'us lawyer' becomes 'DA' (abbreviation for District Attorney).
'pin'+'a'+'cola'+'da'='PINA COLADA'
(Other definitions for pina colada that I've seen before include "alcoholic one" , "Cocktail of rum, pineapple juice and coconut" , "rum-based potation" , "Drink made of pineapple juice, coconut cream and rum" , "Perhaps contents of cocktail glass" .)