Left a half of beer or stout (6)
I believe the answer is:
porter
'stout' is the definition.
(synonyms)
'left a half of beer' is the wordplay.
'left' becomes 'por' (I can't explain this - if you can you should give a lot more credence to this answer).
'a half of' suggests halving the letters.
'beer' becomes 'bitter' (bitter is a type of beer).
'bitter' halved is 'ter'.
'por'+'ter'='PORTER'
'or' is the link.
Can you help me to learn more?
(Other definitions for porter that I've seen before include "One should have no difficulty carrying" , "alcoholic drink" , "Bag carrier in hotel or railway station" , "Doorkeeper; dark beer" , "Drink for a hotel worker" .)