Longman Dictionary of Contemporary English
non-negotiable
adjective
EXAMPLES FROM OTHER ENTRIES
▪ The price is non-negotiable.
EXAMPLES FROM CORPUS
▪ Among the non-negotiable events to be expected during the decade are earthquakes.
▪ Presenting a piece of information as given suggests that it is already established and agreed and is therefore non-negotiable.
Wiktionary
non-negotiable
a. Not negotiable; not subject to negotiation.
Usage examples of "non-negotiable".
You're so used to purchasing whatever you wish by the simple means of your dollars, that you cannot conceive of things that are non-commercial, non-negotiable, non-subject to any kind of trade.