Turf accountant's first drink (4)
I believe the answer is:
soda
'drink' is the definition.
(soda is a kind of drink)
'turf accountant's first' is the wordplay.
'turf' becomes 'sod' (both can mean a piece of grass).
'accountant's first' becomes 'a' (1st letter of 'accountant').
'sod'+'a'='SODA'
(Other definitions for soda that I've seen before include "fizz" , "Whisky mixer" , "kind of water" , "Sodium carbonate" , "In the US, a sweet fizzy drink" .)