Drinker wanting best beer -- just half (5)
I believe the answer is:
toper
'drinker' is the definition.
('toper' can be a synonym of 'drinker')
'best beer just half' is the wordplay.
I cannot quite see how this works, but
'best' could be 'top' ('top' can be similar in meaning to 'best') and 'top' is found within the answer.
The remaining letters 'er' is a valid word which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).
'wanting' is the link.
Can you help me to learn more?
(Other definitions for toper that I've seen before include "Drunkard" , "Someone with a drink problem" , "Serious drinker" , "Soak" , "Drinker, imbiber" .)