non-negotiable

non- +‎ negotiable

non-negotiable (not comparable)

1. Not negotiable; not subject to negotiation.
   • 2023 February 22, Paul Clifton, “Network News: Enhanced role for private sector to fix "broken model"”, in RAIL, number 977, page 7:

     He said: "This is not going to be Network Rail 2.0 or a return to British Rail. Taking politics out of the railways is the only way to build a truly commercially led railway, and for me that is non-negotiable."

Primarily used in two contexts: firstly, to cut off further discussion – “You are not going to marry him – that is non-negotiable!”; secondly, it is printed on pay slips and other payment advice forms (forms that indicate that a payment has been made) to avoid confusion with checks (formally, to indicate that it is informative, and not a negotiable instrument).

• negotiable