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1. A sudden intense happening
   - outburst, burst

1. Ignite quickly and suddenly, especially after having died down
   "the fire flared up and died down once again"
    
2. Erupt or intensify suddenly
   "Unrest flared up in the country"
   - erupt, irrupt, flare, break open, burst out

Derived forms: flared up, flare-ups, flaring up, flares up

Type of: deepen, happening, ignite, intensify, light, natural event, occurrence, occurrent