IPA: /ˌnɒn.nɪˈɡoʊ.ʤə.bəl/
KK: /nɑnˈnɛɡəˌtʃəbl/
Something that cannot be changed or discussed; it is fixed and must be accepted as is.
The terms of the contract are nonnegotiable, so we have to agree to them as they are.
Nonnegotiable → It is formed from "non-" (meaning not) and "negotiable" (from Latin "negotiabilis", meaning able to be negotiated). The word "nonnegotiable" means something that cannot be negotiated or altered.
Think of 'not' ('non-') being combined with 'able to be negotiated' ('negotiabilis') — this helps you remember that nonnegotiable means something that cannot be changed or discussed.