Finally eat stewed ale and duck (4)
I believe the answer is:
teal
'duck' is the definition.
(teal is a type of duck)
'finally eat stewed ale' is the wordplay.
'finally' suggests the final letters.
'stewed' indicates an anagram.
The final letter of 'eat' is 't'.
'ale' is an anagram of 'eal'.
't'+'eal'='TEAL'
'and' is the link.
(Other definitions for teal that I've seen before include "Duck; greenish-blue colour" , "Small river duck" , "Dark greenish-blue colour" , "Small freshwater duck and colour" , "Bluish shade of green" .)