既是可数名词，又是不可数名词。1.患病(状态)、身体不适[U]，此时不可数，例：During his illness，John stayed indoors.约翰在生病期间足不出户。2.(某种)疾病[C]，此时可数。例：I have never seen her since her father fell sick of a illness.
n.疾病，某种具体疾病，不健康
illness可以用作名词
illness不具体指，而是泛指一切疾病，强调生病的时间或状语。
illness是由ill加后缀ness构成的合成词，是“病，疾病”的意思，多指生病的状态。
illness强调疾病的种类时，用作可数名词;表示抽象含义，强调生病的状况时，用作不可数名词。
after illness可指“病愈之后”，也可指“生病以后”。
illness用作名词的用法例句
His illness diminished his health.疾病侵蚀了他的健康。
He will pull through his illness soon.他很快就会恢复健康的。
Worry and illness had made him prematurely old.他心事重重、疾病缠身，落得个未老先衰。
His illness is owing to excessive work.
他由于过度工作而病了。
1.Attitudes to mental illness have shifted in recent years.
最近几年对精神病的态度已有所改变。
2.He boasts of dodging military service by feigning illness.
他炫耀自己通过装病来逃避服兵役。
3.She was determined not to let the illness take hold again.
她决心不让疾病再次击垮自己。
