ill就是完整形式。

adj. 生病的；坏的；邪恶的；不吉利的adv. 不利地；恶劣地；几乎不n. 疾病；不幸I felt ill so I went home.我感到不舒服 于是就回家了。Lee was ill so I went instead.李病了，所以我去了。The patient is terminally ill.这个病人病入膏肓。He fell ill and died soon after.他病倒不久便去世了。She was taken ill suddenly.她突然病倒了。