Christmas lunch? It didn’t go down too well (6)
I believe the answer is:
turkey
I believe this is a double definition.
'christmas lunch?' is the first definition.
(turkey is often eaten at Christmas)
'it didn't go down too well' is the second definition.
(turkey can mean a flop or failure)
(Other definitions for turkey that I've seen before include "A complete flop" , "Bird reared for food" , "Large farmed bird" , "A lemon" , "Country - fowl" .)