不礼貌用英语可以表达为"rude"或"impolite"。这两个词都指不礼貌、无礼或不客气的行为或言论。例句：

It was rude of you to interrupt her while she was speaking. (你打断她说话是不礼貌的。)

He was impolite and didn't even say "thank you" when I held the door open for him. (他很不礼貌，甚至没有说谢谢我为他开门。)

这两个词都来源于拉丁语，"rude"来自拉丁语"rudis"，意为"粗野的"；"impolite"来自拉丁语"impolitus"，意为"不有礼貌的"。