Definition from Wiktionary, the free dictionary
-ность • (-nostʹ)
- Suffix forming nouns denoting the quality of the action designated by the verbs from which the nouns are formed.
- Suffix forming nouns with the meaning of a group of things characterized by the quality designated by the adjectives from which the nouns are formed.
живность ― živnostʹ ― small creatures collectively
Declension of -ность (inan fem-form 3rd-decl accent-a)
- T. F. Yefremova (2006), The New Dictionary of the Russian Language