non-negotiable

not-comparable

Not negotiable; not subject to negotiation.

Japanese Meaning

交渉の余地がない / 交渉不可

Timely payment of the membership fee is non-negotiable and must be completed before the event.

会費の期日通りの支払いは交渉の余地がなく、イベントの前に必ず完了させなければなりません。

Sense（1）

Not negotiable; not subject to negotiation.