Source : Webster's Revised Unabridged Dictionary (1913)

Superannuate \Su`per*an"nu*ate\, v. t. [imp. & p. p.
   {Superannuated}; p. pr. & vb. n. {Superannuating}.] [Pref.
   super- + L. annus a year.]
   1. To impair or disquality on account of age or infirmity.
      --Sir T. Browne.

   2. To give a pension to, on account of old age or other
      infirmity; to cause to retire from service on a pension.

Superannuate \Su`per*an"nu*ate\, v. i.
   To last beyond the year; -- said of annual plants. [Obs.]
   --Bacon.

Source : WordNet®

superannuate
     v 1: retire and pension (someone) because of age or physical
          inability
     2: declare to be obsolete
     3: become obsolete
     4: retire or become ineligible because of old age or infirmity