最初是一个航海术语。当船员生病时，他们会被送往甲板下方以避开恶劣的天气（under the weather deck）。现在泛指感冒、疲劳等小病。

• I won’t be able to come to the party tonight; I’m feeling a bit under the weather. ^{我今晚去不了派对了，我感觉身体有点不舒服。}
• He stayed home because he was slightly under the weather. ^{因为有点小感冒，他留在了家里。}
• You look a bit under the weather; maybe you should take a nap. ^{你看起来气色不太好，也许你应该打个盹。}