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

Following recent water crisis flare-ups, the government is now funding research to understand and address the problem threatening the region’s 22 million residents. —Megan Janetsky, Los Angeles Times, 1 May 2026

Obesity can also raise the risk of developing asthma and worsen symptoms and flare-up frequency in people who already have the condition. —Fran Kritz, Verywell Health, 1 May 2026

Stress is also a common trigger for flare-ups of other conditions like autoimmune diseases, eczema, and irritable bowel syndrome. —Cassie Shortsleeve, Condé Nast Traveler, 30 Apr. 2026

Heat can warp materials or ignite them, and grease flare-ups can send flames higher than expected. —Jessica Safavimehr, Southern Living, 30 Apr. 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