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

Previous flare-ups have calmed after days of fighting, and mediation by foreign governments including Saudi Arabia and Turkey. —Sophia Saifi, CNN Money, 27 Feb. 2026

The rapid and often unpredictable cadence of geopolitical flare-ups means that even the strongest friendshoring partnerships will inevitably be tested. —Angela Velasquez, Sourcing Journal, 25 Feb. 2026

Here's a history of key flare-ups involving the United States and Cuba. —Terry Collins, USA Today, 25 Feb. 2026

Fragrance-free and hypoallergenic mineral sunscreens are generally better to prevent flare-ups. —ABC News, 24 Feb. 2026

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