Entertain a chap with drink (6)
I believe the answer is:
regale
'entertain' is the definition.
(I've seen this in another clue)
'a chap with drink' is the wordplay.
'a chap' becomes 'reg' ().
'with' says to put letters next to each other.
'drink' becomes 'ale' (type of beer).
'reg'+'ale'='REGALE'
(Other definitions for regale that I've seen before include "Entertain with conversation" , "Supply copiously" , "Shower" , "Amuse with stories" , "Feast, give pleasure to" .)