What does "flare up" mean (sense 1)?

For a fire to suddenly burn more intensely. Example: "The campfire flared up when the wind picked up."

What does "flare up" mean (sense 2)?

For a medical condition or symptom to suddenly become worse after a period of calm. Example: "Her arthritis flares up in cold, damp weather."

What does "flare up" mean (sense 3)?

For anger, conflict, or tension to suddenly intensify or re-emerge. Example: "Violence flared up in the capital after the election results were announced."

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flare up

B1 neutral intransitive

For fire to suddenly become more intense; for a feeling, illness, or conflict to suddenly worsen or re-emerge.

In plain English

To suddenly get worse or more intense — said of fires, anger, illness, or conflict.

What does "flare up" mean?

3 meanings, ordered from most common to least. Color-coded by CEFR level.

1 A2 neutral

common

For a fire to suddenly burn more intensely.

"The campfire flared up when the wind picked up."

2 B1 idiomatic neutral

common

For a medical condition or symptom to suddenly become worse after a period of calm.

"Her arthritis flares up in cold, damp weather."

3 B1 idiomatic neutral

very common

For anger, conflict, or tension to suddenly intensify or re-emerge.

"Violence flared up in the capital after the election results were announced."

“

Tensions flared up again along the border.
— BBC News, international reporting, widely used phrasing

Literal vs figurative

Words literally mean

A flare is a sudden burst of flame or light — 'up' reinforces the idea of something shooting upward and intensifying.

Actually means

To suddenly get worse or more intense — said of fires, anger, illness, or conflict.

Usage tip

Extremely versatile. Common in medical contexts (conditions 'flaring up'), emotional contexts (tempers flaring), and news contexts (violence or conflict flaring up). The noun 'flare-up' is also very common. Used in both British and American English.

Words that pair with "flare up"

Natural word combinations native speakers use most often.

temper conflict inflammation violence condition tension fire

How to conjugate "flare up"

The five tense forms you'll use most often.

Base

flare up

I/you/we/they

3rd person

flares up

he/she/it

Past simple

flared up

yesterday

Past participle

flared up

have + pp

-ing form

flaring up

continuous

Hear "flare up" in the wild

Listen to native speakers using "flare up" in real YouTube videos — click a clip to watch it on Looplines.

Other ways to say "flare up"

Swap in when you want variety — tap a linked one to explore it.

blow up break out again erupt intensify recur worsen

Keep exploring

Jump to every phrasal verb built on the same verb, particle, or level.

All phrasal verbs with "flare" All phrasal verbs with "up" More B1-level phrasal verbs