(a) [usu pred 通常作表语] ~ (about/of sth) not knowing definitely 知道得不确切; 无把握: be/feel uncertain (about) what to do 对要做什麽事拿不定主意 * uncertain about/of one's legal rights 不明确自己的合法权利. (b) not known definitely 未被确切了解: The outcome is still uncertain. 结果仍不明朗. 
not to be depended on; unreliable 靠不住; 不可信赖: His aim is uncertain. 他的目标不明确. 
likely to vary; changeable 可能改变; 常变化: uncertain weather 变幻莫测的天气 * a man of uncertain temper 喜怒无常的人. 
hesitant or tentative 犹豫; 迟疑不决: an uncertain voice, smile 吞吞吐吐的说话声﹑ 似笑非笑 * the baby's first uncertain steps 婴儿初学行走时不稳的脚步. 
(idm 习语) in ,no un,certain `terms clearly and forcefully 清楚而有力地: I told him what I thought of him in no uncertain terms! 我毫不含糊地把我对他的看法告诉了他!> uncertainly adv hesitantly 犹豫地; 迟疑地: speak, wait uncertainly 吞吞吐吐地说﹑ 左右为难地等候.
uncertainty / Qn5s\:tntI; Qn`s[tntI/ n (a) [U] state of being uncertain 无把握; 不确定; 变化不定; 犹豫: The uncertainty is unbearable! 事情定不下来难以忍受! (b) [C esp pl 尤作复数] thing which is uncertain 无把握﹑ 不确定或变化不定的事物: the uncertainties of life on the dole, ie as an unemployed person 依靠救济金生活的不安定.