/mæd ||; mæd/adj1 having a mind that does not work normally; mentally ill 疯癫的；精神失常的
It is not usual nowadays to use mad or insane to describe a person who is not mentally normal. We use the expression mentally ill. 形容某人精神有问题，如今通常不用mad或insane，而用mentally ill。2 (Brit 英) not at all sensible; crazy 傻的；愚蠢的；荒唐的: You must be mad to drive in this weather. 你在这种天气里驾车简直是发疯了。
3 (not before a noun 不用于名词前) mad (at/with sb) (about sth) very angry 极为愤怒；十分恼火: His laziness drives me mad! 他这样懒惰，真把我气死了！ (especially US 尤为美) Don't get/go mad at him. He didn't mean to do it. 不要恼他，他不是有心这样做的。
4 (informal 非正式)mad about/on sb/sth liking sb/sth very much 非常喜欢；对…着迷: He's mad on computer games at the moment. 他此刻正沉迷于计算机游戏。Steve's mad about Jane. 史蒂夫迷恋着简。
5 not controlled; wild or very excited 不受控制的；狂乱的；十分兴奋的: The audience was cheering and clapping like mad (= very hard). 观众疯狂地欢呼鼓掌。When DiCaprio appeared on the hotel balcony his fans went mad. 当狄卡普里欧出现在酒店阳台上的时候，他的影迷们简直疯了。