under the weather

Feeling sick; ill. It can also mean that a person is feeling sad or depressed.

不舒服； 身體不適

in the old days, when a sailor was feeling seasick, "he was sent down below to help his reocvery, under the deck and away from the weather."

來源是這樣子，以前在航海時，當水手暈船時，他就會躲到甲板，這樣就遠離糟糕的天氣，所以用under the weather 來指代心情不好，或感覺不舒服；

He cannot come to the class today because he is under the weather.

今天他不能來上課，因為他身體不舒服。

Jessica just got back from her vacation in Florida, but sadly, she returned feeling a bit under the weather because she had a sore throat, a runny nose, and a fever.

Jessica剛從Florida度假回來，但是她的心情有點糟，因為她發燒，嗓子啞了而且還發燒。