Nothingness (8)
'nothingness' is the definition.
(I know that nothingness can be written as nullity)
This is the entire clue.
(Other definitions for nullity that I've seen before include "Nothingness" , "State of being void" , "being without force" , "Invalid act" .)
'nothingness' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for oblivion that I've seen before include "State of being forgotten and disregarded" , "ignorance" , "Total extinction" , "lack of fame" , "The state of being unconscious of what is happening" .)