Entertain fellow with beer (6)
I believe the answer is:
regale
'entertain' is the definition.
(I've seen this in another clue)
'fellow with beer' is the wordplay.
'fellow' becomes 'reg' (I can't justify this - if you can you should give a lot more credence to this answer).
'with' is a charade indicator (letters next to each other).
'beer' becomes 'ale' (type of beer).
'reg'+'ale'='REGALE'
Can you help me to learn more?
(Other definitions for regale that I've seen before include "Ply" , "Entertain royally" , "Feed or entertain well" , "Feast, give pleasure to" , "Entertain, delight" .)