1640s, "inexplicable," from un- (1) "not" + accountable. Meaning "not liable to be called to account" is recorded from 1640s. Related: Unaccountably; unaccountability; unaccountableness.
实用例句
1. For some unaccountable reason, it struck me as extremely funny.
不知道为什么，我觉得这极其滑稽。
来自柯林斯例句
2. He had an unaccountable change of mind.
他莫名其妙地改变了主意。
来自柯林斯例句
3. For some unaccountable reason, the letter never arrived.
不知何故，那封信始终未寄到。
来自《权威词典》
4. An insane person is unaccountable for his actions.
