Source : Webster's Revised Unabridged Dictionary (1913)

Decrepitude \De*crep"i*tude\, n. [Cf. F. d['e]cr['e]pitude.]
   The broken state produced by decay and the infirmities of
   age; infirm old age.

Source : WordNet®

decrepitude
     n : a state of deterioration due to old age or long use [syn: {dilapidation}]