Source : Webster's Revised Unabridged Dictionary (1913)

Unreality \Un`re*al"i*ty\, n.
   The quality or state of being unreal; want of reality.

Source : WordNet®

unreality
     n 1: the quality possessed by something that is unreal [ant: {reality}]
     2: the state of being insubstantial or imaginary; not existing
        objectively or in fact [syn: {irreality}] [ant: {reality}]