Rare, chiefly literary or philosophical use meaning 'the void' or 'empty space'.
Translations
The spacecraft disappeared into the inane, swallowed by the darkness of space.
Le vaisseau spatial a disparu dans le vide, englouti par l'obscurité de l'espace.
Definitions
The void; empty or limitless space, especially beyond the earth’s atmosphere (rare). The spacecraft disappeared into the inane, swallowed by the darkness of space.