hard-and-fast
['ha:dn'fa:st]
adj. 严格的, 不可违逆的, 必须遵守的
例句与用法：
A hard worker.
勤奋的工人
He achieved because he was a hard worker.
他之所以成功是因为他工作勤奋。
He is not so much a genius as a hard worker.
他的努力胜于天分。
详细释义：
a.
不容变更的; 严格的
His parents have no hard-and-fast rules about how late he can stay out.
他的父母对他可以在外逗留多晚并没有严格的规定。