non-negotiable rules

noun phrase
UK /ˌnɒn nɪˈɡəʊʃiəbl ruːlz/
US /ˌnɑːn nɪˈɡoʊʃiəbl ruːlz/

Rules that you must follow and cannot change.

Wearing a helmet is one of the non-negotiable rules for riding a bike.


OTHER MEANINGS

2. Rules in a game or sport that players are not allowed to argue about or alter.

The referee reminded the teams that the non-negotiable rules of the tournament would be enforced.

3. Firm conditions in a deal or agreement that cannot be discussed or changed.

The landlord listed non-negotiable rules about pets and noise in the lease.

4. Personal limits someone sets for themselves that they refuse to break.

For her, honesty and kindness are non-negotiable rules in any friendship.