Dubious about new drink (6)
I believe the answer is:
shandy
'drink' is the definition.
(I know that shandy is a type of drink)
'dubious about new' is the wordplay.
'dubious' becomes 'shady' (I've seen this in another clue).
'about' indicates putting letters inside.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'shady' enclosing 'n' is 'SHANDY'.
(Other definitions for shandy that I've seen before include "A misture of ale and lemonade" , "Beer/lemonade mixture" , "Drink made of beer and lemonade" , "Alcohol" , "Beer/lemonade drink" .)