1. the symbol or banner of a left-wing revolutionary party.
2. a danger signal.
3. something that provokes an angry or hostile reaction: The talk about raising taxes was a red flag to many voters. 4. Also called powder flag.Naut.a red burgee, designating in the International Code of Signals the letter “B,” flown by itself to show that a vessel is carrying, loading, or discharging explosives or highly inflammable material.
5. (caps.) a war game the U.S. Air Force holds several times each year at Nellis Air Force Base, Nevada, to train personnel in air combat.
—v.t. 1. to mark or draw attention to for a particular purpose: The department has red-flagged the most urgent repair work to be done. 2. to provoke the attention of; alert; arouse: The animal's refusal to eat red-flagged the keeper that something was wrong.
—adj. 1. of or pertaining to a red flag.
2. intended or serving to emphasize, warn, incite, or provoke.