Source : Webster's Revised Unabridged Dictionary (1913)

Infirmity \In*firm"i*ty\, n.; pl. {Infirmities}. [L. infirmitas
   : cf. F. infirmite. See {Infirm}, a.]
   1. The state of being infirm; feebleness; an imperfection or
      weakness; esp., an unsound, unhealthy, or debilitated
      state; a disease; a malady; as, infirmity of body or mind.

            'T is the infirmity of his age.       --Shak.

   2. A personal frailty or failing; foible; eccentricity; a
      weakness or defect.

            Will you be cured of your infirmity ? --Shak.

            A friend should bear his friend's infirmities.
                                                  --Shak.

            The house has also its infirmities.   --Evelyn.

   Syn: Debility; imbecility; weakness; feebleness; failing;
        foible; defect; disease; malady. See {Debility}.

Source : WordNet®

infirmity
     n : the state of being weak in health or body (especially from
         old age) [syn: {frailty}, {debility}, {feebleness}, {frailness}]