English Reference
phrasal verb · noun

flare up

phr.v. · n.

  1. 01 B2 Upper Intermediate

    phr.v.to suddenly burn more brightly or strongly.

    phr.v.to burst into sudden, intense flame or light after a period of lower activity.

    Simple

    The campfire flared up when he threw a handful of dry leaves onto the embers.

    In context

    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. 02 B2 Upper Intermediate Medicine

    phr.v.to suddenly become worse after being better for a while.

    phr.v.to recur or intensify suddenly, typically used in a medical context for chronic conditions.

    Simple

    Her skin allergy tends to flare up whenever she is under a lot of stress.

    In context

    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.

    recurworsen
  3. 03 B2 Upper Intermediate

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

    phr.v.to erupt into sudden anger, violence, or social unrest.

    Simple

    Tempers flared up during the meeting when the manager mentioned the new budget cuts.

    In context

    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. 04 B2 Upper Intermediate

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

    n.a sudden outburst or recurrence of a condition, emotion, or conflict.

    Simple

    The doctor said the flare-up was caused by a change in his diet.

    In context

    The recent flare-up in regional violence has prompted international observers to call for an immediate ceasefire.

    Teacher's tip

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

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.

Particles
up
Separability
inseparable
Pattern
flare + up
This entry
Level B2 · Upper Intermediate
Frequency Frequent
Updated