Red flags

A red flag in dating is an early sign that someone treats you, or other people, in a way you would not accept later. It is a warning, not a verdict. Unlike the ick or a mismatch in taste, it is about behavior, so the test is whether it repeats and gets worse when you mention it.

Updated October 5, 2026

Means

Early warning signs in a relationship

First seen

Figurative 'red flag' since the 18th century; the dating sense has no dated first use

Related terms

Green flags, Love bombing, The ick, Beige flags, Breadcrumbing

In Swedish

Red flags

Search for red flags and you get long lists where “chews with their mouth open” sits a few lines above “reads your messages.” Those are not the same kind of thing.

Signs you are looking at a red flag (and not a bad day)

Everyone has an off evening. A red flag is the thing that is still there on the good evenings. Five tests help separate the two.

• It repeats. One sharp comment is an incident. The same comment on the third date and the seventh is information.
• It gets worse when you name it. You mention it calmly and get anger, a joke at your expense, or a version of events in which you started it. A compliment with a put-down built in, and “you can’t take a joke” when you name it, is negging.
• It is about how they treat people, not what they like. Hating your favorite band is taste. Snapping at the bartender is behavior.
• Your friends noticed first. They brought it up before you had said a word.
• You have started explaining them to yourself. “He’s just tired.” “She didn’t mean it like that.” If you are drafting their defense in advance, you already know the charge.

A useful frame comes from a 2016 dissertation by White, which borrowed signal detection theory from psychology (White, 2016). Any warning system makes two kinds of mistake. A false alarm is reacting to something harmless. A miss is waving through something real. Treat every quirk as a red flag and you get a lot of false alarms. Explain everything away and you get misses. The job is to check the signal before deciding what it means.

Red flags vs dealbreakers, yellow flags and the ick

Dating has collected a whole rack of flags. The colors mean different things, and mixing them up is how the lists get so long.

• Red flag. A pattern in someone’s behavior that says something about how they are likely to treat you. It is about them.
• Dealbreaker. A fixed no, and you are the one who sets it. They want kids and you don’t, or they smoke and you can’t stand it. Nobody is doing anything wrong. It just won’t work.
• Yellow flag. BetterUp’s term for a less severe warning sign, something to raise and sort out together rather than leave (BetterUp, 2024). Late twice in a row, say, or a vague answer about the last relationship.
• The ick. A sudden, often trivial turn-off, like the way they run for a bus. The ick is real enough, but it is aesthetic. It tells you about your attraction, not their character.
• Beige flag. A harmless quirk, neither good nor bad. The phrase made Oxford’s Word of the Year shortlist in 2023 (Oxford Languages, 2023).

The opposite of a red flag is a green flag, a sign you would like to see more of.

Red flags by stage

The warning signs on a first date are not the ones that matter a year in.

On a first date

• Rude to the waiter, the bartender or the driver.
• Phone on the table, and in their hand, for most of the evening.
• Talks about the ex longer than about anything else, including you.
• Looks noticeably different from the photos. One old photo is kittenfishing, and a pattern of small fibs is the flag.
• Drinks a good deal more than the evening calls for.
• Pushes to know where you live, or to walk you home after you said no.

In the talking stage

• Hot and cold. Warm for three days, silent for four, then back as if nothing happened.
• Endless texting, no plan. Plenty of “we should meet,” never a day. That is close to breadcrumbing.
• Too much, too early. Big declarations before you have met twice can be love bombing. Vivid plans for a shared future, attached to a request now, can be future faking.
• Asks for photos early, and keeps asking after you change the subject.

Once you are exclusive

• They decide how your time is spent, or which friends are worth seeing.
• They check your phone, or want your passcode as proof of something.
• Every argument ends with you apologizing, whoever started it.
• You have begun leaving things out when you talk to friends, to avoid a discussion at home.

The last one describes your behavior, not theirs. People tend to notice it early and admit it late. If the person asks for money, threatens to share images or turns out to be using someone else’s photos, the law is on is catfishing illegal.

What to do about it

A red flag tells you where to look. These steps get you an answer without months of guessing.

1. Sort it first. Is it a value, a behavior or a taste? Taste is yours to act on without a conversation. A value clash is a dealbreaker check. Behavior is the one worth raising.
2. Name it once, plainly. No speech, no examples from three weeks ago. “When you talk to waiters like that, I don’t like it.”
3. Watch the reaction, not the apology. Sorry is cheap. What counts is the following week, and whether you are suddenly the one being blamed.
4. Treat one repeat after that as the pattern. You raised it, they heard it, it happened again. A third round will not tell you anything new.
5. Leave early, with one line. Ending after three dates takes a text, and our ghosting page has two lines you can use. Ending after a year takes a moving van. “I don’t think this is right for me, so I’m going to stop here.”
6. If you feel afraid, controlled or physically threatened, skip the conversation and get help first. US: thehotline.org. UK: refuge.org.uk.

What the research says

Less research than the lists suggest.

The closest thing to a researched red-flag list comes from Csajbók and colleagues. They had 285 US students rate 49 negative characteristics in a potential partner. The ratings clustered into six groups: gross, addicted, clingy, promiscuous, apathetic and unmotivated. For a long-term partner, apathetic and gross put people off the most (Csajbók et al., 2023).

White’s dissertation at Louisiana State University looked at how people pick up undesirable qualities in early romantic encounters, and sorted relational red flags into nine main types (White, 2016). It is a dissertation, not a peer-reviewed paper. The signal-detection framing is the part worth keeping.

If you have read about warning signs in long relationships, you have probably met John Gottman’s four horsemen: criticism, contempt, defensiveness and stonewalling. It is a framework from his work with married couples. The Gottman Institute cites a 93.6% accuracy figure for predicting divorce, from a 1992 study by Buehlman, Gottman and Katz (Gottman Institute, 2026). Those were marriages already under way, observed in a lab. The figure says nothing about a first date.

That is the gap. We found no study showing that the usual listed red flags predict later harm. The research measures what people say would put them off. That tells you what a lot of people will not tolerate. It does not tell you what happens if you do.

The phrase is much older than dating apps. Etymonline gives 1777 for “red flag” as a figurative warning (Etymonline, 2026). We found no dictionary that dates the dating sense, so we will not guess at one.