Food at back only half edible (5)
I believe the answer is:
table
'edible' is the definition.
(thesaurus)
'food at back only half' is the wordplay.
'food' becomes 'b' (B is an example).
'back' says the letters should be written in reverse.
'only' becomes 'sole' (synonyms).
'half' suggests halving the letters.
'b'+'at'='bat'
'bat' in reverse letter order is 'tab'.
'sole' cut in half is 'le'.
'tab'+'le'='TABLE'
(Other definitions for table that I've seen before include "Item of furniture; figures presented in columns" , "Flat board on legs" , "Array of figures" , "Dummy hand (bridge)" , "Flat-topped piece of furniture" .)