Root beer or ginger ale (4)
I believe the answer is:
soda
'root beer or ginger ale' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for soda that I've seen before include "Mixer drink" , "Fizzy drink - chemical compound" , "Drink containing carbonated water and sometimes flavouring" , "fizz" , "Sodium carbonate" .)