1 (US 美 sick) (not before a noun 不用于名词前) not in good health; not well 生病；身体不适: I can't drink milk because it makes me feel ill. 我不能喝牛奶，一喝就觉得难受。My mother was taken ill suddenly last week. 妈妈上个礼拜突然病了。My grandfather is seriously ill in hospital. 爷爷躺在医院里，病得很厉害。 ☞Look at the note at sick. 参看sick的注释。

2 (only before a noun 只用于名词前) bad or harmful 坏的；有害的: He resigned because of ill health. 他因为身体不好，辞职了。I'm glad to say I suffered no ill effects from all that rich food. 虽然我吃了那么油腻的东西，可庆幸什么事也没有。 ☞noun illness 名词为illness