Severely criticise traditional Sunday lunch (5)
I believe the answer is:
roast
This clue is a double definition.
'severely criticise' is the first definition.
(I've seen this before)
'traditional sunday lunch' is the second definition.
(I've seen this before)
(Other definitions for roast that I've seen before include "Carpet" , "Sunday meal" , "Cook with dry heat" , "Criticise severely" , "traditional meal" .)