最佳答案
反义词加前缀的单词是improper，例如：
1.Laughing and joking are improper at a funeral.葬礼时大笑和开玩笑是不合适的。
2.The improper use of medicine could lead to severe adverse reactions.用药不当会产生严重的不良反应。
3.He would never be improper, he is always the perfect gentleman.他总是举止得体，一直是个完美的绅士。
proper的反义词加前缀
proper反义词是improper，加前缀im-