What is the meaning of under weather?

"Under the weather" is an idiom meaning not feeling well, slightly ill. It's a casual way of saying someone is unwell, but not necessarily seriously ill.

Here are some examples of how it's used:

* "I'm feeling a bit under the weather today, so I'm going to stay home."

* "She's been under the weather all week, but she's finally starting to feel better."

* "Don't worry about being late; I'm just a little under the weather."

The origin of the idiom is unclear, but it's believed to have come from sailors who felt unwell during rough weather conditions.