un-/ʌn-; ʌn-/ prefix 1 used at the beginning of words to mean 'not' 不: unhappy 不高兴的 unexpected 预料之外的 2 used at the beginning of some verbs, meaning to do the opposite of the meaning of the verb, especially when talking about removing things 〔用于表示做相反的动作，尤在谈及移动东西时〕: undress (=take off your clothes) 脱衣 unfasten 松开