From nothing + -ness.

nothingness (uncountable)

1. The state of nonexistence; the condition of being nothing.
   • 1818, John Keats, “Book I”, in Endymion: A Poetic Romance, London: […] T[homas] Miller, […] for Taylor and Hessey, […], →OCLC ↗, page 3 ↗, lines 1–5:

     A thing of beauty is a joy for ever: / Its loveliness increases; it will never / Pass into nothingness; but still will keep / A bower quiet for us, and a sleep / Full of sweet dreams, and health, and quiet breathing.

2. A void; an emptiness.
3. The quality of inconsequentiality; the lack of significance.

• (state of nonexistence) nihility; See also Thesaurus:inexistence

• (antonym(s) of “state of nonexistence”): existence; See also Thesaurus:existence

• do-nothingness
• good-for-nothingness
• know-nothingness

• French: néant
• German: Nichtvorhandensein, Nichts
• Italian: nulla
• Portuguese: vacuidade
• Russian: тлен

• French: vide
• German: Nichts, Leere
• Portuguese: vazio

• German: Bedeutungslosigkeit