The Collaborative International Dictionary of English v.0.48:

Fragility \Fra*gil"i*ty\, n. [L. fragilitas: cf. F.
   fragilit['e]. Cf. Frailty.]
   1. The condition or quality of being fragile; brittleness;
      frangibility. --Bacon.
      [1913 Webster]

   2. Weakness; feebleness.
      [1913 Webster]

            An appearance of delicacy, and even of fragility, is
            almost essential to it [beauty].      --Burke.
      [1913 Webster]

   3. Liability to error and sin; frailty. [Obs.]
      [1913 Webster]

            The fragility and youthful folly of Qu. Fabius.
                                                  --Holland.
      [1913 Webster]

WordNet (r) 3.0 (2006):

fragility
    n 1: quality of being easily damaged or destroyed [syn:
         fragility, breakability, frangibleness,
         frangibility]
    2: lack of physical strength [syn: fragility, delicacy]

Moby Thesaurus II by Grady Ward, 1.0:

68 Moby Thesaurus words for "fragility":
   amiable weakness, breakability, breakableness, brittleness,
   cachexia, cachexy, changeableness, chronic ill health, collapse,
   crackability, crackableness, crispness, crumbliness, crushability,
   crushableness, daintiness, debilitation, debility, decrepitude,
   delicacy, delicate health, destructibility, disintegration,
   effeminacy, enervation, exhaustion, feebleness, fissility,
   flimsiness, fracturableness, frailty, frangibility, friability,
   healthlessness, human frailty, hypochondria, hypochondriasis,
   ill health, indecisiveness, infirmity, infirmity of will,
   inherent vice, invalidism, invalidity, irresolution, lacerability,
   languishing, languishment, lightness, moral weakness, morbidity,
   morbidness, peakedness, poor health, sickliness, sleaziness,
   slightness, unhealthiness, unsoundness, unsubstantiality,
   unwholesomeness, valetudinarianism, velleity, vulnerability,
   wasting, weakliness, wispiness, womanishness