volatile /ˈvɔlətail/ adj. 易挥发的；反复无常的，易变的：a highly volatile liquid一种极易挥发的液体With the markets being so volatile, investments are at great risk.由于市场那么变化不定, 投资冒着很大的风险。Beware of his volatile moods!小心他变化无常的情绪！