Hammered after failing to get first bit bolted down (5)
I believe the answer is:
eaten
'bolted down' is the definition.
'hammered after failing to get first bit' is the wordplay.
'hammered' becomes 'beaten' (I've seen this before).
'after failing to get first bit' means to remove the first letter.
'beaten' with its first letter removed is 'EATEN'.
(Other definitions for eaten that I've seen before include "This bread is soon forgotten, it's said" , "corroded" , "Scoffed" , "used for food" , "Consumed" .)