The Colorful Terms We Use to Describe Behavioral Cues

It isn't always as easy as this to read other people's cues

Source: GPT-4o / OpenAI

Everyone, it seems, has advice about dating and relationships. Contemporary discussions of these topics often involve red flags or warning signs, and green flags or desirable qualities, in a potential partner. But where did these terms come from? As it happens, one is quite old, whereas the other is relatively recent.

Seeing Red

The red flag has a long history in English, with the Oxford English Dictionary attesting its use as early as 1585. The phrase originally referred to a nautical banner signaling that a ship’s crew was ready for battle. Red flags were also commonly employed as symbols of defiance. By the mid-18th century, the term had broadened into a generic stand-in for any sort of warning.

The color red was seen as the natural choice for warning signs in the first traffic lights. These began to appear during the 1860s and were initially gas-lit and manually operated. By the time of World War I, flashing red lights, powered by electricity, were in use at railroad crossings. These were followed by the familiar three-color traffic signals deployed at intersections beginning in the 1920s.

Red pennants are used to indicate small craft and gale warnings, and a red flag with a black square at its center serves as a warning for storms and hurricanes. The color red—linked to both blood and to fire—is intimately associated with real or anticipated threats or danger. It’s easy to see how red flag was adapted as a term for deal-breaking behaviors committed by potential romantic partners.

Going Green

The term green flag, however, is a contemporary coinage. Green flags have been used since the 1930s to signal the beginning of auto races, as well as the resumption of racing after a caution period. At the beach, a green flag can signal safe swimming conditions. And of course, green means go at intersections. But when did people start using this color to refer to a person’s attractive or desirable traits?

You’ll search in vain for the green flag in the Oxford or Merriam-Webster dictionaries: the term hasn’t been added to those word lists yet. A little sleuthing is required to find the earliest examples of its usage in an interpersonal context.

References to green flags began to appear, for example, in articles on Psychology Today’s website as early as March 2010. Initially, however, it referred to ethical conduct by therapists. And articles referring to red flags typically contrasted these signs with green lights—not green flags.

The earliest example I could find of green flag being used in the context of relationships was a July 2013 post on Reddit, the popular social media platform. A contribution to the subreddit r/AskWomen was titled “Ladies, What Are Your 'Green Flags'”? The use of quotation marks is instructive, as it suggests the author didn’t consider the term to be well-known.

It wasn’t until April 2019 that a Psychology Today post employed green flag in the context of interpersonal relations (in “What a Relationship with a Parent Reveals About a Partner”). The term was not commonly used on the site until about 2023.

Analogical Creativity

The process by which red flags led to green flags is familiar to linguists: it’s called analogical extension. A term with a well-known meaning serves as the basis for a new concept—often its opposite—by analogy.

A good example is the term outro, first attested in 1967. It was formed by analogical extension from intro (first used in 1923). Another is white market—authorized commerce, dating from 1943, formed by analogy from the much-earlier black market (1727).

References to special effects in films date from 1907, and only much later, in the early 1980s, was the term practical effect coined by analogy. And bromance (2001), from the much earlier romance (1844), is yet another example of extension via the blending of terms.

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True Colors?

Perhaps inevitably, red and green flags have been joined by other colorful variations, such as yellow flags, which can signal that caution is warranted. This term appeared on Reddit (in r/AskWomen) as early as February 2015 (“What is a ‘yellow flag’ for you in relationships?”). It became topical enough that a July 2024 New York Times story was titled “Slow Down if You See These Dating ‘Yellow Flags.’”

Finally, the beige flag popped up on Reddit as early as April 2021 (“How to deal with a ton of beige flags?” in r/dating_advice). These can be thought of as generic or minor quirks that don’t reveal much about a person.

Discussions of beige flags were soon appearing on TikTok and other social media platforms, and the concept was discussed in a New York Times article in June 2023. A few months later, beige flags made it to the linguistic big leagues: it was shortlisted as Oxford’s Word of the Year.

Forming accurate impressions of the people we meet can be difficult—but at least we have a colorful vocabulary to describe the signals that we see, hear, and obsess over.