instability (n.)youdaoicibaDictYouDict[instability 词源字典]
early 15c., from Middle French instabilite "inconstancy," from Latin instabilitatem (nominative instabilitas) "unsteadiness," from instabilis "unsteady," from in- "not, opposite of" (see in- (1)) + stabilis (see stable (2)).[instability etymology, instability origin, 英语词源]