Sustainable is an adjective not a noun
At some point sustainability moved from being used as a adjective to a noun, from a word used to describe a state – a sustainable future; to a word used to define a person or thing – a sustainability consultant or a sustainable building.
In this shift from adjective to noun it has diluted the inherent meaning of the word – able to be maintained at a certain rate or level; Conserving an ecological balance by avoiding depletion of natural resources.
There are signs that society is shifting back to the adjective, a complacency or distrust of the noun is gaining ground – maybe a total move away from sustainability as a noun to a shift back to sustainable as an adjective will generate the sustainable action we need.
Thank you to my seven year old daughter who is teaching me about verbs, nouns and adjectives!