Flare  —v. (-ring) 1 widen gradually (flared trousers). 2 (cause to) blaze brightly and unsteadily. 3 burst out, esp. Angrily. —n. 1 a dazzling irregular flame or light. B sudden outburst of flame. 2 flame or bright light used as a signal or to illuminate a target etc. 3 a gradual widening, esp. Of a skirt or trousers. B (in pl.) Wide-bottomed trousers.  flare up burst into a sudden blaze, anger, activity, etc. [origin unknown]