Source : Webster's Revised Unabridged Dictionary (1913)

Obsoleteness \Ob"so*lete*ness\, n.
   1. The state of being obsolete, or no longer used; a state of
      desuetude.

   2. (Biol.) Indistinctness; want of development.

Source : WordNet®

obsoleteness
     n : the property of being out of date and not current [syn: {superannuation}]