Drink in local occasionally served up (4)
I believe the answer is:
cola
'drink' is the definition.
(I know that cola is a type of soft drink)
'in local occasionally served up' is the wordplay.
'in' says the answer is hidden in the clue.
'served up' shows that the letters should be reversed in order.
'aloc' is hidden in the letters of 'local occasionally'.
'aloc' in reverse letter order is 'COLA'.
(Other definitions for cola that I've seen before include "Cold drink" , "pop" , "Carbonated soft drink" , "Fizzy drink" .)