[mass noun]lack of stability; the state of being unstable 不稳定,不稳固 political and economic instability. 政治和经济的不稳定。 ■tendency to unpredictable behaviour or erratic changes of mood 行为无常;情绪不定
语源
late Middle English: from French instabilité, from Latin instabilitas, from instabilis, from in- 'not' + stabilis (see stable)