1、瘋的，神經錯亂的，精神失常的 adj.
I think I must be going mad.
我想我肯定要瘋了。
Do I look like some mad old woman in this hat?
我戴上這頂帽子看上去像個瘋老太婆嗎？

2、極其愚笨的;發瘋的
[ + to infinitive ] You're mad to walk home alone at this time of night.
你發瘋了，晚上這個時候獨自一人走回家。
He must be mad spending all that money on a coat.
他一定是瘋了，花那麼多錢買一件外套。
Some of the things she does are completely mad.
她做的一些事情極其愚蠢。

3、非常憤怒的，狂怒的；十分惱火的
He's always complaining and it makes me so mad.
他沒完沒了地抱怨，令我十分惱火。
mainly US Are you still mad at me?
你還在生我的氣嗎？
UK Kerry got really mad with Richard for not doing the washing up.
理查沒有洗碗碟，克麗大發雷霆。
UK Bill's untidiness drives me mad.
比爾的邋遢真讓我受不了。

4、發瘋似的;忙亂的
We made a mad dash for the train.
我們發瘋似的去趕火車。
I was in a mad panic/rush trying to get everything ready.
我發瘋似的急急忙忙想把一切準備好。

★be mad about sb/sth. 喜愛，對…著迷
He's the first real boyfriend she's had and she's mad about him.
他是她第一個真正的男朋友，她很迷戀他。
He's mad about football.
他對足球著迷。