Don't allow bread to spoil (5)

I believe the answer is:

debar

I'm a little stuck... Click here to teach me more about this clue!

'don't allow' is the definition.
I can't tell whether this definition defines the answer.

'bread to spoil' is the wordplay.
'to spoil' is an anagram indicator.
'bread' is an anagram of 'DEBAR'.

Can you help me to learn more?

(Other definitions for debar that I've seen before include "Refuse to admit" , "Shut out, preclude" , "Exclude (from doing something)" , "Block" , "Blackball" .)

I've seen this clue in the Evening Standard.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.