1640s, from un- (1) "not" + past participle of balance (v.). Earliest use is in reference to the mind, judgment, etc. Of material things, it is recorded from 1732.
权威例句
1. The centre of pressure moves rearward and the aeroplane becomes unbalanced.
气压中心后移使飞机失去平衡。
2. I knew how unbalanced Paula had been since my uncle Peter died.
我知道葆拉自从我叔叔彼得去世后情绪一直很不稳定。
3. He was shown to be mentally unbalanced.
他被证明精神有问题。
4. UN officials argued that the report was unbalanced.