IPA: //nɒnɪkˈspɛndəbl//
KK: /nɑnɪkˈspɛndəbl/
Something that cannot be used up or replaced; it is essential and must be preserved.
The resources we have are nonexpendable, so we need to use them wisely.
Nonexpendable → It is formed from "non-" (meaning not) and "expendable" (from Latin "expendere", meaning to spend or to use up). The word "nonexpendable" means not able to be spent or used up, indicating something that cannot be wasted or is essential.
Think of 'not' ('non-') being combined with 'able to be spent' ('expendable') — that's why nonexpendable means something that cannot be wasted.