# flare up

Source: https://englishreference.com/word/flare-up
Updated: 2026-08-08

## Senses

### 1. fire or light

phrasal verb · CEFR B2

to suddenly burn more brightly or strongly.

For teachers: to burst into sudden, intense flame or light after a period of lower activity.

- The campfire flared up when he threw a handful of dry leaves onto the embers.
- The fire flared up unexpectedly as the wind shifted, forcing the emergency crews to retreat several yards for safety.

Usage: Intransitive; does not take a direct object.

### 2. illness or pain

phrasal verb · CEFR B2

to suddenly become worse after being better for a while.

For teachers: to recur or intensify suddenly, typically used in a medical context for chronic conditions.

- Her skin allergy tends to flare up whenever she is under a lot of stress.
- Patients often report that their joint pain flares up during periods of cold, damp weather or following strenuous physical activity.

Usage: Intransitive; the subject is usually the symptom or the condition.

### 3. anger or violence

phrasal verb · CEFR B2

to suddenly become very angry or for a conflict to start again.

For teachers: to erupt into sudden anger, violence, or social unrest.

- Tempers flared up during the meeting when the manager mentioned the new budget cuts.
- Long-standing tensions between the two rival factions flared up again following the controversial announcement at the border.

Usage: Intransitive; often used with 'tempers' as the subject.

### 4. a sudden outburst

noun · CEFR B2

a sudden period of increased activity, anger, or illness.

For teachers: a sudden outburst or recurrence of a condition, emotion, or conflict.

- The doctor said the flare-up was caused by a change in his diet.
- The recent flare-up in regional violence has prompted international observers to call for an immediate ceasefire.

Teaching tip: Note the hyphenation in the noun form 'flare-up', which distinguishes it from the phrasal verb.

## Examples

- My back pain tends to flare up when it is cold.
- Violence began to flare up in the city after the new laws were announced by the government.
- Although the chronic infection appeared to be in remission, the symptoms would occasionally flare up during periods of extreme physical exhaustion.

## Usage notes

- Teaching tip: use the image of a fire suddenly getting bigger to help students remember the meaning for abstract things like anger or skin rashes.

---

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.