unaccountable
adj. 无责任的；莫名其妙的；不可理解的
比较级 more unaccountable
最高级 most unaccountable
例句
For some unaccountable reason, the letter never arrived.
不知何故，那封信始终未寄到。
《牛津词典》
For some unaccountable reason, it struck me as extremely funny.
很难解释是什么原因让我觉得它极为可笑。
《柯林斯英汉双解大词典》
Economic policy should not be run by an unaccountable committee of governors of central banks.
经济政策不应该由中央银行行长组成的不负责任的委员会来施行。
