1. (n.) The quality or condition of being unstable; want of stability, firmness, or steadiness; liability to give way or to fail; insecurity; precariousness; as, the instability of a building.

2. (n.) Lack of determination of fixedness; inconstancy; fickleness; mutability; changeableness; as, instability of character, temper, custom, etc.

ambitendency ambivalence caducity capriciousness chanciness change of mind changeability changeableness choppiness corruptibility criticalness danger dappleness death decrepitude delicacy desultoriness deviability deviation difference differentiation disorder divarication divergence diversification double-mindedness doubtfulness dubiety dubiousness eccentricity ephemerality ephemeralness erraticism evanescence fence-sitting fence-straddling fickleness finitude fleetingness flightiness freakishness fugacity hazard hazardousness impermanence impermanency impulsiveness incapacity inconsistency inconstancy indecision indecisiveness inequality infirmity infirmity of purpose insecurity insipidity insolidity insubstantiality invalidism irregularity irresolution jerkiness mercuriality momentariness moodiness mortality motleyness mugwumpery mugwumpism mutability nonconformism nonconformity nonstandardization nonuniformity peril perilousness perishability pluralism precariousness raggedness restlessness ricketiness risk riskiness second thoughts senility shakiness shiftiness shiftingness slipperiness speculativeness sword of Damocles tergiversation ticklish business ticklishness totteriness touchiness transience transiency transientness transitoriness treacherousness treachery unauthenticity unauthoritativeness uncertainty unconformism unconformity undecidedness undependability undeterminedness unevenness unfaithworthiness unfirmness unfixedness unhealthiness unorthodoxy unpredictability unreliability unsafeness unsettledness unsettlement unsolidity unsoundness unstableness unsteadfastness unsteadiness unsturdiness unsubstantiality unsureness untrustworthiness vapidity variability variation variegation variety variousness versatility volatility wantonness wateriness wavering waywardness whimsicality wishy-washiness