The Collaborative International Dictionary of English v.0.48:

Fragile \Frag"ile\, a. [L. fragilis, from frangere to break; cf.
   F. fragile. See Break, v. t., and cf. Frail, a.]
   Easily broken; brittle; frail; delicate; easily destroyed.
   [1913 Webster]

         The state of ivy is tough, and not fragile. --Bacon.

   Syn: Brittle; infirm; weak; frail; frangible; slight. --
        Frag"ile*ly, adv.
        [1913 Webster]

WordNet (r) 3.0 (2006):

fragile
    adj 1: easily broken or damaged or destroyed; "a kite too
           delicate to fly safely"; "fragile porcelain plates";
           "fragile old bones"; "a frail craft" [syn: delicate,
           fragile, frail]
    2: vulnerably delicate; "she has the fragile beauty of youth"
    3: lacking substance or significance; "slight evidence"; "a
       tenuous argument"; "a thin plot"; a fragile claim to fame"
       [syn: flimsy, fragile, slight, tenuous, thin]

Moby Thesaurus II by Grady Ward, 1.0:

93 Moby Thesaurus words for "fragile":
   breakable, brittle, brittle as glass, capricious, changeable,
   cheap-jack, cobwebby, corruptible, crackable, crisp, crispy,
   crumbly, crushable, dainty, deciduous, decrepit, delicate,
   delicately weak, dying, effeminate, ephemeral, evanescent, fading,
   feeble, fickle, fissile, fleeting, flimsy, flitting, fly-by-night,
   flying, fracturable, frail, frangible, friable, fugacious,
   fugitive, gimcrack, gimcracky, gossamery, impermanent, impetuous,
   impulsive, inconstant, infirm, insubstantial, jerry, jerry-built,
   lacerable, light, lightweight, momentary, mortal, mutable,
   namby-pamby, nondurable, nonpermanent, papery, passing,
   pasteboardy, perishable, puny, rickety, scissile, shaky,
   shatterable, shattery, shivery, short, short-lived, sissified,
   sleazy, slight, splintery, tacky, temporal, temporary, tenuous,
   thin, transient, transitive, transitory, undurable, unenduring,
   unsound, unstable, unsubstantial, volatile, vulnerable, weak,
   weakly, wispy, womanish



The Jargon File (version 4.4.7, 29 Dec 2003):

fragile
 adj.

    Syn brittle.


The Free On-line Dictionary of Computing (30 December 2018):

brittle
fragile

    Said of software that is functional but easily
   broken by changes in operating environment or configuration,
   or by any minor tweak to the software itself.  Also, any
   system that responds inappropriately and disastrously to
   abnormal but expected external stimuli; e.g. a file system
   that is usually totally scrambled by a power failure is said
   to be brittle.  This term is often used to describe the
   results of a research effort that were never intended to be
   robust, but it can be applied to commercially developed
   software, which displays the quality far more often than it
   ought to.

   Opposite of robust.

   [Jargon File]

   (1995-05-09)