flare up

1 to become very angry naturally I flared up when he insulted my girlfriend Synonyms blow up (up), flip (out) [slang]Related Words anger, fulminate, rage, rant, rave, snap, snarl, sputter, storm, tee off, vent, vituperate; bristle, burn, foam, fume, glare, glower, seethe, sizzle, smolder (or smoulder), steam, warm; burst, explode, blow up (out), flash, inflame (also enflame), maddenNear Antonyms chill out [slang], cool (off or down), relax; hush, quiet (down)Antonyms calm (down), simmer down

2 to develop suddenly and violently her cold sores flared up again when she got the flu Synonyms blaze (up), break out, burst (forth), explode, flame, erupt (up)Related Words rocket, skyrocket; balloon, burgeon (also bourgeon), mount, multiply, mushroom, proliferate, snowball, swell, wax; blow up, detonate, touch off