Thus get attorney beverage (4)
I believe the answer is:
soda
'beverage' is the definition.
(soda is a kind of beverage)
'thus get attorney' is the wordplay.
'thus' becomes 'so' (synonyms).
'get' is a charade indicator (letters next to each other).
'attorney' becomes 'D.A.' (District Attorney).
'so'+'da'='SODA'
(Other definitions for soda that I've seen before include "Accompaniment to whisky" , "Variety of pop" , "Splash served with some spirits" , "Fizzy drink - chemical compound" , "for use with whisky?" .)