# dangerous

/ˈdeɪndʒɝəs/ (US) · /dˈeɪndʒəɹəs/ (UK)

Source: https://englishreference.com/word/dangerous
Updated: 2026-06-19

## Senses

### 1. likely to cause harm

adjective · CEFR A1

likely to cause physical harm, injury, or death.

For teachers: involving or causing exposure to injury, pain, or loss. This is the primary sense used for physical hazards.

- It is dangerous to walk on the thin ice during the spring thaw.
- The mountain pass becomes exceptionally dangerous during the winter months when heavy snowfall obscures the narrow trail and increases the risk of avalanches.

### 2. threatening or aggressive

adjective · CEFR A2

describes a person or animal that is likely to attack or hurt others.

For teachers: characterised by a disposition to inflict harm or injury; often used to describe volatile individuals or aggressive animals.

- The police warned the public that the escaped tiger was very dangerous.
- The suspect was considered armed and dangerous, prompting the authorities to issue a high-level alert to all surrounding residential areas.

### 3. critically ill

adjective · CEFR C1 · Formal · Archaic

very sick and at risk of dying.

For teachers: referring to a medical state where a patient's life is at immediate risk. This usage is increasingly rare in modern speech but remains in specific medical or literary contexts.

- The doctor said the patient's condition was dangerous after the long surgery.
- The bulletin released by the hospital confirmed that the prime minister remained in a dangerous state following the sudden cardiac event.

## Examples

- It is dangerous to walk on the thin ice.
- The mountain road becomes extremely dangerous during the winter months when heavy snow covers the sharp turns.
- While the chemical is stable under normal laboratory conditions, it becomes highly dangerous if exposed to direct sunlight or high temperatures for extended periods.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.