What does "indispensableness" mean?

The characteristic of being indispensable; indispensability.

What is a synonym for "indispensableness"?

Common synonyms include: indispensability, necessity, vitalness.

noun

noun ·Rare ·Advanced level

Noun

1
The characteristic of being indispensable; indispensability. uncountable
2
the quality possessed by something that you cannot possibly do without wordnet

From indispensable + -ness.