red flag

¹ American  

noun

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.  Nautical. 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. (initial capital letters) 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.

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red-flag ² American  

[red-flag] / ˈrɛdˈflæg /

verb (used with object)

red-flagged, red-flagging

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.

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adjective

1. of or relating to a red flag.

2. intended or serving to emphasize, warn, incite, or provoke.

red flag ¹ British  

noun

1. a symbol of socialism, communism, or revolution

2. a warning of danger or a signal to stop

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Red Flag ² British  

noun

1. a socialist song, written by James Connell (1852–1929), Irish political activist, in 1889

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Etymology

Origin of red flag¹

First recorded in 1770–80

Origin of red-flag²

First recorded in 1880–85

Example Sentences

So when D.C.’s proposal crossed our desk with similar red flags, we took a closer look.

From The Wall Street Journal

Their relative normalcy, and that of fellow marrieds Amber Morrison and Jordan Faeth, is a soothing contrast to the textbook Fusco fiasco and the rest of the season’s red flag bearers.

From Salon

If someone is standing on the curb trying to get you to come in, that is also a red flag.

From Barron's

Neighbors said the property never raised red flags, though some noticed unusual activity over time.

From Los Angeles Times

As much as the start of daylight-saving time prompts some economic researchers to raise financial red flags, Shuai, the Chmura vice president, says the real issue goes beyond that.

From MarketWatch