Genial Reg mixed drink (6,3)
I believe the answer is:
ginger ale
'drink' is the definition.
(ginger ale is a kind of drink)
'genial reg mixed' is the wordplay.
'mixed' is an anagram indicator.
'genial'+'reg'='genialreg'
'genialreg' is an anagram of 'GINGER ALE'.
(Other definitions for ginger ale that I've seen before include "It won't make you drunk!" , "One drink" , "Spicy, sweetened non-alcoholic drink" , "Fizzy drink" , "pop" .)