Drink cola when out with dad (7)
I believe the answer is:
alcopop
'drink' is the definition.
(type of alcoholic drink)
'cola when out with dad' is the wordplay.
'when out' indicates an anagram (out can mean incorrect or inaccurate).
'with' means one lot of letters go next to another.
'dad' becomes 'pop' (synonyms).
'cola' is an anagram of 'alco'.
'alco'+'pop'='ALCOPOP'
(Other definitions for alcopop that I've seen before include "fizzy drink" , "drink young people like" , "Smooth out" , "Intoxicating beverage tasting like a soft drink" , "Sweet pub drink" .)