It’s impolite to gibe at a foreign student’s English.

嘲笑国学生英语是不礼貌。

It is impolite to get a word in.

别人谈话时插嘴是不礼貌。

It’s impolite to make a tardy appearance.

晚到是不礼貌。

"If you thought he intended to be impolite, you were mistaken."

"如果你认为他是故意粗鲁无礼,那你就误会了。"

He wasn’t just impolite—he was downright rude.

他不仅仅是不礼貌，而是无礼透顶。

She ordered that impolite fellow out.

她责令那个无礼家伙出去。

His impolite words angered his teacher.

他出言不逊, 激怒了他老师。