Baked bread hamper (5)
I believe the answer is:
debar
'hamper' is the definition.
(both can mean to prevent someone doing something)
'baked bread' is the wordplay.
'baked' indicates an anagram.
'bread' with letters rearranged gives 'DEBAR'.
(Other definitions for debar that I've seen before include "Exclude from a place" , "Blackball" , "Refuse to admit" , "Large advert" , "Exclude, prohibit" .)