red flag: meaning, definition, pronunciation and examples

High
UK/ˌred ˈflæɡ/US/ˌrɛd ˈflæɡ/

Informal to Formal (context-dependent)

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Quick answer

What does “red flag” mean?

A literal red-colored flag used as a warning signal (e.

Audio

Pronunciation

Definition

Meaning and Definition

A literal red-colored flag used as a warning signal (e.g., in motor racing, on beaches).

A sign or signal indicating a potential problem, danger, or reason for caution, especially regarding behavior, character, or a situation.

Dialectal Variation

British vs American Usage

Differences

No significant difference in core meaning or usage. Both use the term extensively in the metaphorical sense.

Connotations

Identical strong negative warning connotation in both varieties.

Frequency

Equally high frequency in both varieties, with a slight modern increase in American media discussing relationships and workplace culture.

Grammar

How to Use “red flag” in a Sentence

[Something] is/was a red flag[Someone] raised a red flag about [something][Verb] a red flagA red flag for [something]

Vocabulary

Collocations

strong
major red flaghuge red flagraise a red flagwave a red flagconstitute a red flag
medium
see a red flagspot a red flagignore a red flagbig red flagclear red flag
weak
little red flagpossible red flagpotential red flagred flag appeared

Examples

Examples of “red flag” in a Sentence

verb

British English

  • The auditor red-flagged several transactions for further review.
  • I must red-flag that proposal on ethical grounds.

American English

  • The system automatically red-flags any login from an unfamiliar location.
  • Her history was red-flagged during the background check.

adverb

British English

  • (Not standard; no adverbial form in use.)

American English

  • (Not standard; no adverbial form in use.)

adjective

British English

  • He displayed several red-flag behaviours during the interview.
  • We keep a list of red-flag indicators for fraud.

American English

  • That's a major red-flag statement from a potential partner.
  • The report highlighted red-flag conditions in the contract.

Usage

Meaning in Context

Business

Refers to indicators of financial risk, ethical breaches, or operational failures in due diligence.

Academic

Used in psychology, sociology, and medicine to denote warning signs of a condition or problematic behavior.

Everyday

Commonly used in discussions about relationships, dating, friendships, and online interactions.

Technical

In computing/IT, can refer to system alerts or flags in code review; in motorsport/aviation, the literal flag.

Vocabulary

Synonyms of “red flag”

Strong

danger signalportentharbinger

Neutral

warning signcause for concernalarm bell

Weak

something to notepoint of caution

Vocabulary

Antonyms of “red flag”

Watch out

Common Mistakes When Using “red flag”

  • Using it as a verb incorrectly (e.g., 'He red-flagged' is less common; prefer 'He raised a red flag').
  • Overusing for trivial issues, diluting its warning strength.
  • Misspelling as one word 'redflag'.

FAQ

Frequently Asked Questions

Yes, in its modern metaphorical sense, it exclusively indicates a warning, problem, or danger.

Yes, especially in formal/business contexts (e.g., 'to red-flag an issue'), though 'raise a red flag' is more common in everyday speech.

A red flag is a warning sign that suggests a potential problem. A dealbreaker is a specific issue that makes you reject something entirely. Multiple red flags can lead to a dealbreaker.

Its literal use dates back centuries as a signal of danger (e.g., in railways, military). The metaphorical use became widespread in the 20th century.

A literal red-colored flag used as a warning signal (e.

Red flag is usually informal to formal (context-dependent) in register.

Red flag: in British English it is pronounced /ˌred ˈflæɡ/, and in American English it is pronounced /ˌrɛd ˈflæɡ/. Tap the audio buttons above to hear it.

Phrases

Idioms & Phrases

  • A red flag to a bull (something that provokes anger)

Learning

Memory Aids

Mnemonic

Think of a bullfighter's RED cape (flag) – it signals DANGER and makes you want to STOP.

Conceptual Metaphor

POTENTIAL PROBLEM IS A WARNING SIGNAL (COLOR RED).

Practice

Quiz

Fill in the gap
His constant criticism of your friends is a serious in the relationship.
Multiple Choice

In a business context, what does 'red flag' most likely refer to?