fragile adj.

late 14c., "moral weakness," from Old French fragilité "debility, frailty" (12c.), from Latin fragilitatem (nominative fragilitas) "brittleness, weakness," from fragilis "brittle, easily broken," from root of frangere "to break" (from PIE root *bhreg- "to break"). Meaning "quality of being easily broken" is from late 15c.

Proto-Indo-European root meaning "to break."

It forms all or part of: anfractuous; Brabant; bracken; brake (n.1) "stopping device for a wheel;" brake (n.2) "kind of fern;" brash; breach; break; breccia; breeches; brioche; chamfer; defray; diffraction; fractal; fraction; fractious; fracture; fragile; fragility; fragment; frail; frangible; infraction; infringe; irrefragable; irrefrangible; naufragous; ossifrage; refract; refraction; refrain (n.); refrangible; sassafras; saxifrage; suffragan; suffrage.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit (giri)-bhraj "breaking-forth (out of the mountains);" Latin frangere "to break (something) in pieces, shatter, fracture;" Lithuanian braškėti "crash, crack;" Old Irish braigim "break wind;" Gothic brikan, Old English brecan "to break."

mid-14c., "morally weak," from Old French fraile, frele "weak, frail, sickly, infirm" (12c., Modern French frêle), from Latin fragilis "easily broken" (from PIE root *bhreg- "to break"). It is the Frenchified form of fragile. Sense of "easily destroyed, liable to break" in English is from late 14c. The U.S. slang noun meaning "a woman" is attested from 1908; perhaps with awareness of Shakespeare's "Frailty, thy name is woman."