Stop cooking bread (5)
I believe the answer is:
debar
'stop' is the definition.
(I've seen this before)
'cooking bread' is the wordplay.
'cooking' indicates anagramming the letters (letters cooked up into a new form).
'bread' anagrammed gives 'DEBAR'.
(Other definitions for debar that I've seen before include "Exclude from a place" , "Exclude (from right)" , "Exclude (from doing something)" , "Exclude, prohibit" , "Keep out" .)