early 15c., "too large to be conceived, unimaginable," from un- (1) "not" + think (v.) + -able. Meaning "incapable of being framed by thought" is recorded from mid-15c.
实用例句
1. Edward VIII had done the unthinkable and abdicated the throne.
爱德华八世竟主动逊位，真是匪夷所思。
来自柯林斯例句
2. Any thought of splitting up the company was unthinkable they said.
他们说，任何将公司拆分开的想法都是不能接受的。
来自柯林斯例句
3. Her strong Catholic beliefs made abortion unthinkable.
