Knock down for consuming half a loaf (5)
I believe the answer is:
floor
'knock down' is the definition.
(synonyms)
'for consuming half a loaf' is the wordplay.
'consuming' is an insertion indicator.
'half a' means to take half the letters.
'loaf' halved is 'lo'.
'for' enclosing 'lo' is 'FLOOR'.
(Other definitions for floor that I've seen before include "Stump" , "Part of building" , "Fox" , "Defeat" , "at bottom of forest" .)