Dictionary.com
Thesaurus.com
Jump To:
  • red flag
    red flag
    noun
    the symbol or banner of a left-wing revolutionary party.
  • red-flag
    red-flag
    verb (used with object)
    to mark or draw attention to for a particular purpose.
  • Red Flag
    Red Flag
    noun
    a socialist song, written by James Connell (1852–1929), Irish political activist, in 1889
Synonyms

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 flagNautical. 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.


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.


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

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Red Flag 2 British  

noun

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

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of red flag1

First recorded in 1770–80

Origin of red-flag2

First recorded in 1880–85

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

When the safety car pulled in, Ferrari's Charles Leclerc crashed, which led to the race being suspended under a red flag.

From BBC • Jun. 19, 2026

Celebrities giving financial advice is a red flag for John Nowicki.

From The Wall Street Journal • Jun. 15, 2026

The index this high often is a red flag that stocks are overpriced—and about to drop.

From Barron's • Jun. 10, 2026

This was either a red flag or a very Los Angeles credential, depending on the neighborhood.

From Los Angeles Times • Jun. 5, 2026

The next week the squadron won the red flag, and Lieutenant Scheisskopf was beside himself with rapture.

From "Catch-22" by Joseph Heller

Vocabulary.com logo
by dictionary.com

Look it up. Learn it forever.

Remember "red flag" for good with VocabTrainer. Expand your vocabulary effortlessly with personalized learning tools that adapt to your goals.

Take me to Vocabulary.com