flare-up

noun

ˈfler-ˌəp 

1

: a sudden outburst or intensification

a flare-up of hostilities

2

: a sudden bursting (as of a smoldering fire) into flame or light

a danger of flare-ups

3

: a sudden appearance or worsening of the symptoms of a disease or condition

an asthmatic flare-up

Synonyms of flare-up

• flurry
• burst
• outburst
• outbreak
• flare

Examples of flare-up in a Sentence

took medication to prevent a flare-up of her asthma

there's no need for an angry flare-up, as we'll take care of the problem immediately

Recent Examples on the Web

The flare-up of cross-border tension is just the latest challenge to a tenuous ceasefire agreement between the neighbors that came into effect in mid-October, and relations between Islamabad and Kabul have been fraught since the Taliban swept back to power in 2021. —CBS News, 25 Nov. 2025

For now, Treasury yields are down across the curve, underscoring how the market is in no mood to price in an inflation flare-up soon, even when talk of more-aggressive Fed easing gets loud. —Michael Santoli, CNBC, 25 Nov. 2025

Large, messy sunspots that mingle or merge are especially fertile sites for flare-ups. —Meghan Bartels, Scientific American, 19 Nov. 2025

Fetterman, who has been open about his mental and physical health struggles, recently fell due to a ventricular fibrillation flare-up while on a walk in Pennsylvania. —Molly Parks, The Washington Examiner, 19 Nov. 2025

Word History

First Known Use

1839, in the meaning defined at sense 1

Rhymes for flare-up

• buttercup
• backup
• blowup
• breakup
• buildup
• checkup
• cleanup
• holdup
• hookup
• lineup
• lockup
• makeup

Kids Definition

flare-up

noun

ˈfla(ə)r-ˌəp, 

ˈfle(ə)r-

: a sudden burst (as of flame or anger)

Medical Definition

flare-up

noun

-ˌəp 

: a sudden appearance or worsening of the symptoms of a disease or condition

an asthmatic flare-up