under the weather沿用至今有一百五十来年了。有人推测这个习惯用语原来可能指有的人由于海上风急浪高而晕船，感到身体不舒服。现在，under the weather就是身体不适，微恙。

【例句】
Are you feeling better now or are you still under the weather?
你现在感觉好点了还是仍然不舒服？

She just phoned to tell me she's under the weather today. She's come down with a headache and a bad cough so she can't go out with me tonight.
她刚打来电话告诉我她今天身体不适。她头很疼，又咳嗽得厉害，所以今晚不能和我一起出去了。