v. & n.
v. 1 intr. & tr. widen or cause to widen gradually towards the top or bottom (flared trousers). 2 intr. & tr. burn or cause to burn suddenly with a bright unsteady flame. 3 intr. burst into anger; burst forth.
n. 1 a a dazzling irregular flame or light, esp. in the open air. b a sudden outburst of flame. 2 a a signal light used at sea. b a bright light used as a signal. c a flame dropped from an aircraft to illuminate a target etc. 3 Astron. a sudden burst of radiation from a star. 4 a a gradual widening, esp. of a skirt or trousers. b (in pl.) wide-bottomed trousers. 5 an outward bulge in a ship's sides. 6 Photog. unnecessary illumination on a lens caused by internal reflection etc. flare-path an area illuminated to enable an aircraft to land or take off. flare up 1 burst into a sudden blaze. 2 become suddenly angry or active. flare-up n. an outburst of flame, anger, activity, etc.
[ 16th c.: orig. unkn. ]