Down dinner (3)
I believe the answer is:
eat
'down dinner' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for eat that I've seen before include "Use a knife and fork" , "Corrode" , "Ingest" , "Do cats - bats? Do bats - cats? (Alice in Wonderland)" , "Partake of" .)