'Flare-up' definitions:

Definition of 'flare-up'

From: WordNet
noun
A sudden intense happening; "an outburst of heavy rain"; "a burst of lightning" [syn: outburst, burst, flare-up]

Definition of 'Flare-up'

From: GCIDE
  • Flare-up \Flare"-up`\, n.
  • 1. A sudden burst of anger or passion; an angry dispute. [Colloq.] [1913 Webster]
  • 2. A sudden bursting into flame; a flaring. [Webster 1913 Suppl.]