1
- not in full health; sick生病的, 不舒服的：
her daughter is seriously ill
她女儿病得很严重
with submodifier a terminally ill patient.病入膏肓者。
2
- attrib. poor in quality坏的, 差的, 次的：
ill judgement dogs the unsuccessful.
错误的判断往往紧随着不成功的人士。
2.1
- harmful有害的：
she had a cup of the same wine and suffered no ill effects.
她也喝了杯同样的酒, 却没有受到伤害。
2.2
- hostile恶意的：
I bear you no ill will.
我对你没有任何恶意。
2.3
- (especially of fortune) not favourable（尤指运气）不顺的：
no one less deserved such ill fortune than McStay.
麦克斯代比谁都不应该有这样的霉运。
1
- usu. in combination badly, wrongly, or imperfectly糟糕地; 错误地; 有缺陷地：
some of his premises seem ill-chosen
看来他的一些前提选择不当
it ill becomes one so beautiful to be gloomy.
这么美的人不应这么忧郁。
1.1
- unfavourably or unpropitiously不利地; 不吉利地, 不祥地：
something which boded ill for unwary golfers.
粗心大意的高尔夫球手们的不祥之兆。
2
- only with difficulty; hardly艰难地; 几乎不：
she could ill afford the cost of new curtains.
她几乎出不起钱买新窗帘。
1
- as plural noun the ill people who are ill病人, 患者：
a day centre for the mentally ill.
精神病人日间照管中心。
2
- （一般作ills）a problem or misfortune问题; 灾祸, 不幸：
a lengthy work on the ills of society.
一部关于社会问题的长篇作品。
2.1
- mass noun evil; harm厄运; 邪恶; 伤害, 损害：
how could I wish him ill?
我怎能希望他倒霉呢？
短语
ill at ease
- uncomfortable or embarrassed不安; 局促。
speak（或think）ill of
- say (or think) something critical about苛责, 批评, 说…的坏话, 把…想得很坏。
词源
Middle English （in the senses 'wicked', 'malevolent', 'harmful', and 'difficult'）： from Old Norse illr 'evil, difficult', of unknown origin.