VERB (4)

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;

The Collaborative International Dictionary of English v.0.48:

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.
      [1913 Webster]

   2. To give a pension to, on account of old age or other
      infirmity; to cause to retire from service on a pension.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Superannuate \Su`per*an"nu*ate\, v. i.
   To last beyond the year; -- said of annual plants. [Obs.]
   --Bacon.
   [1913 Webster]

WordNet (r) 3.0 (2006):

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

Moby Thesaurus II by Grady Ward, 1.0:

100 Moby Thesaurus words for "superannuate":
   abdicate, age, antiquate, be pensioned, be superannuated,
   be superseded, become extinct, become obsolete, boot, bounce,
   break, bump, bust, can, cashier, date, deconsecrate, defrock,
   degrade, demit, demote, deplume, depose, deprive, dethrone, disbar,
   discharge, discrown, disemploy, disenthrone, dismiss, displace,
   displume, drum out, excommunicate, expel, fade, fall into disuse,
   fire, fossilize, furlough, fust, give the ax, give the gate,
   give up, go out, grow old, junk, kick, kick upstairs, lay off,
   leave, let go, let out, liquidate, lose currency, make redundant,
   molder, obsolesce, obsolete, oust, outdate, overthrow, pass away,
   pension, pension off, perish, purge, quit, read out of, release,
   relinquish, remove, remove from office, renounce the throne,
   replace, resign, retire, retire from office, rust, sack, scrap,
   separate forcibly, stand aside, stand down, step aside, strip,
   strip of office, strip of rank, surplus, suspend, turn off,
   turn out, unchurch, unfrock, unsaddle, unseat, unthrone, vacate,
   withdraw from