Exclude new bread (5)
I believe the answer is:
debar
'exclude' is the definition.
(synonyms)
'new bread' is the wordplay.
'new' indicates anagramming the letters.
'bread' is an anagram of 'DEBAR'.
(Other definitions for debar that I've seen before include "Rule out" , "Shut out, preclude" , "Formally prevent" , "Keep out" , "Ban" .)