ill

Compared meaning: feeling physically unwell (adjective).

比较义项：感觉身体不适（形容词）。

• sick

  Describes a queasy stomach and the urge to vomit, often from food, smells, or motion; a specific symptom, not general illness.

  指胃里翻腾、想呕吐的感觉，常由食物、气味或晕动引起；是一种具体的身体症状，而不是笼统的生病状态。

  The strong smell of the fish made her feel sick.

  那股浓烈的鱼腥味让她感到恶心想吐。

• ill 本词

  A more general and slightly more formal word for being unwell or having an illness, often more serious or longer-lasting than a single symptom.

  泛指身体不健康或患病，语气比sick稍正式，通常指比单一症状更严重或持续更久的病况。

  He has been seriously ill with a fever for a week.

  他发烧了，已经病得很严重一个星期了。

• dizzy

  Describes a spinning, unsteady sensation in the head, often linked to loss of balance rather than nausea or general sickness.

  指头部旋转、站不稳的感觉，多与失去平衡有关，而不是恶心或泛指的生病。

  Standing up too fast left him feeling dizzy and off balance.

  他起身太快，感到头晕、站不稳。

Sick, ill, and dizzy can describe feeling unwell. Sick means nauseous, wanting to vomit. Ill is a general, slightly formal word for being unwell. Dizzy means your head spins and you feel unsteady. Not compared: sick as 'tired of' and ill as 'harmful'.

这三个词都能用来描述身体不舒服，但侧重不同：sick强调恶心、想吐，ill泛指生病、身体不健康，dizzy强调头晕、站不稳。这里不比较sick表示「厌烦」（如be sick of）或ill作「有害的、恶劣的」（如ill effects）等其他用法。

Compared meaning: bad or harmful (adjective).

比较义项：不良的，有害的（形容词）。

• ill 本词

  Mild, literary word for 'bad' or 'unfavorable', mostly used before a noun in fixed phrases like 'ill effects' or 'ill health'; rarely used to describe strong damage.

  语气较轻、偏书面语，表示“不良的”或“不利的”，多用在名词前的固定搭配中，如“ill effects”（不良影响）或“ill health”（欠佳的健康状况）；很少用来描述严重的损害。

  Doctors warned that fast food has many ill effects on children's health.

  医生警告说，快餐会对儿童健康产生许多不良影响。

• catastrophic

  Strongest word, describing sudden, severe, disastrous consequences on a large scale, often for events like floods, fires, or failures.

  语气最强，形容突然、严重、大规模的灾难性后果，常用于洪水、火灾或重大失败等事件。

  A catastrophic wildfire destroyed thousands of homes within a single night.

  一场灾难性的野火在一夜之间摧毁了数千所房屋。

• harmful

  Neutral, common word for causing damage or injury, used broadly for health, substances, or the environment; works well alone or with 'to'.

  中性且常用的词，表示造成损害或伤害，广泛用于健康、物质或环境等语境；可单独使用，也可接“to”。

  Excessive screen time can be harmful to young children's eyesight.

  过度使用电子屏幕的时间可能对幼儿的视力有害。

• detrimental

  Formal synonym for harmful, almost always followed by 'to', common in academic or official writing about long-term negative effects.

  harmful 的正式同义词，几乎总是接“to”，常见于学术或官方文体中描述长期的负面影响。

  Skipping breakfast every day can be detrimental to your metabolism.

  每天不吃早餐可能对新陈代谢有害。

Ill, catastrophic, harmful, and detrimental describe something bad, but strength differs. Catastrophic is strongest: sudden, severe disaster. Harmful and detrimental both mean causing harm; detrimental is more formal, usually with 'to'. Ill is mildest, in fixed phrases like 'ill effects'. Not compared: ill meaning 'sick'.

这四个词都可以表示“造成负面影响的”，但程度和用法不同：catastrophic 语气最强，指突然而严重的灾难性破坏；harmful 和 detrimental 都表示“有害的”，其中 detrimental 更为正式，常接 to；ill 语气最轻，多用于固定搭配，如 ill effects、ill health。这里不比较 ill 表示“生病的”这一更常见的义项。