Heard green drink is sweet (8)
I believe the answer is:
lollipop
'is sweet' is the definition.
(I've seen this before)
'heard green drink' is the wordplay.
I cannot quite understand how this works, but
'drink' could be 'pop' (pop is a kind of drink) and 'pop' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for lollipop that I've seen before include "Woman seeing children safely across the road" , "Boiled sweet" , "Ice confection" , "Sweetmeat" , "Sucked sweet" .)