What does it mean if someone says he is under the weather? It has nothing to do with weather, actually! DEFINITION: It means to feel ill, not healthy. Especially when the illness is not very serious and you don't know what it is or you don't want to be specific. EXAMPLE: "I'm feeling a bit under the weather - I think I'm getting a cold." The same term is sometimes used as a euphemism for being drunk, as in: "After four drinks, Ellen was a bit under the weather." So, if your friend is under the weather bringing him some vitamins can save his day!