The Oxford Thesaurus An A-Z Dictionary of Synonyms - oblivionn.

1) blankness, blackness, darkness, obscurity, nothingness, nihility, anonymity, extinction, non-existence, void, limbo: The rock band enjoyed brief fame, then sank into oblivion. 2) unawareness, obliviousness, forgetfulness, heedlessness, disregard, unconsciousness, insensibility: I sank back into the sweet oblivion of deep sleep.