Stout from cask brought into bar (6)
I believe the answer is:
rotund
'stout' is the definition.
(I've seen this in another clue)
'cask brought into bar' is the wordplay.
'cask' becomes 'tun' (tun is a kind of cask).
'brought into' is an insertion indicator.
'bar' becomes 'rod' (both can mean a pole or stick).
'tun' placed within 'rod' is 'ROTUND'.
'from' is the link.
(Other definitions for rotund that I've seen before include "Chubby" , "Round and plump" , "Large and plump" , "Rather obese" , "Grandiloquent; podgy" .)