Good Polish food (4)
I believe the answer is:
grub
'food' is the definition.
(I know that food can be written as grub)
'good polish' is the wordplay.
'good' becomes 'g' (abbreviation).
'polish' becomes 'rub' (polish meaning rub to make shiny).
'g'+'rub'='GRUB'
(Other definitions for grub that I've seen before include "Worm-like larva of an insect" , "Nosh - larva" , "food, commonly" , "Dig (up); hack writers' Street" , "Common food" .)