There are many different kinds of friends. Aristotle distinguished among friendships based on utility, pleasure, and virtue. Michel de Montaigne wrote about true friendship, which “grows up, is nourished and improved by enjoyment, as being of itself spiritual, and the soul growing still more refined by its practice.” In this column, I have written about the difference between real friends and deal friends.

And then there is the frenemy. This portmanteau of friend and enemy first appeared as long ago as the late 19th century. It signifies a discordant relationship in which someone appears to be your friend or has a superficially friendly demeanor toward you but behaves in ways that real friends wouldn’t and shouldn’t. Perhaps the frenemy undermines you, manipulates your feelings, gaslights you, or says mean things about you behind your back.

Identifying frenemies isn’t always easy, because the behavior can be designed to go undetected, or perhaps to be so subtle that you wonder if you’re being paranoid. Or sometimes you just don’t want to face the truth: This person actually does not wish you well. But looking for the telltale signs of a frenemy and taking action to distance yourself from the person are very worthwhile for your own health and happiness.

Arthur C. Brooks: How to worry less and be happier

Frenemies comprise a broad category, because outwardly friendly people can find a lot of ways to do unfriendly things to you. Even so, three basic frenemy types, which can occur together or in isolation, emerge from the research.

1. The competitive frenemy
In 2022, a group of scholars identified three common characteristics of the frenemy relationship: competitiveness (in which the relationship is marked by rivalry, at work or in personal lives), jealousy (due to envy of social connections, material possessions, or some other advantage), and distrust (because animus prevents honesty). This dynamic might occur between you and a co-worker with whom you seem to be on amiable terms but who, say, is willing to take credit for your work. Or they might be someone who would very much like to supplant you with your romantic partner. You may be on good terms at one level, but your spider-sense tells you to stay vigilant because betrayal feels like a possibility.

2. The two-faced frenemy
And betrayal is not just a possibility with the frenemy; it is a real threat. This person is supportive and friendly to your face, but is all too ready to trash-talk you behind your back. Scholars in 2019 identified this kind of frenemy in research on bullying behavior. They interviewed adults who had been bullied and found that they typically spoke of a supposed friend who, in the researchers’ words, was “pro-victim when alone with the victim” but turned “neutral or pro-aggressor when surrounded by members of the bullying circle.” This might be a co-worker who listens with earnest sympathy when you talk about your problems with your boss, and later tells the boss what you said and yuks it up with her about what an incompetent loser you are.

3. The manipulative frenemy
Adult bullies in the workplace and similar contexts tend to use relational aggression, such as social exclusion, gossip, and rumors. These tactics create actual enemies. Frenemies are generally subtler, relying on less overtly aggressive means to get what they want from another person. One typical strategy is emotional manipulation, which researchers studying same-sex female friendships have found is particularly prevalent when one partner believes in its effectiveness. The two most common are called “worsening strategies” (undermining confidence, either through direct criticism or by sharing negative feedback from others) and “inauthentic strategies” (sulking or going silent to get one’s way). These qualities characterize Machiavellianism, a personality pathology characterized by low empathy and high cynicism. In surveys, these manipulative frenemies—the ones who score high in Machiavellianism—tend to agree with such statements as The best way to handle people is to tell them what they want to hear.

Arthur C. Brooks: The sociopaths among us—and how to avoid them

All three types of frenemy sound pretty awful. Still, people tend to put up with known frenemies for a long time without taking action. This seems like paradoxical behavior: If someone undermines you, betrays you, and manipulates you, why on earth would you maintain any relationship with them? In one recent scholarly article, three authors investigated this question, asking people why they maintain “frenemyships” instead of keeping their distance, as one would with an actual foe. They proposed at least three primary reasons: saving face by avoiding a conflict, maintaining a social network, and because the relationship is useful. In other words, breaking away from a frenemy might seem too costly or inconvenient.

Still, you should avoid frenemies whenever you can, because, as researchers have argued, their ambivalent effect on you may net out as more negative than positive owing to forces such as cardiovascular stress, blood pressure, depressed mood, and interpersonal conflict. Frenemies are worse for you even than out-and-out foes, according to psychologists writing in the journal Health Psychology. The researchers tested the physiological effects of dealing with people with whom we have an ambivalent relationship—in which, for example, we don’t really like or trust the other person but are outwardly friendly nonetheless. They showed that blood pressure tends to rise more in such interactions than in encounters both with real friends and with actual enemies.

If you’re now questioning a few of your ambivalent relationships, you might be wondering how to test for whether someone actually fits the frenemy description. To answer this, we need first to establish what a true friend is. Researchers at McGill University broke the role of friendship into six basic dimensions. In 2007, researchers in the Journal of Happiness Studies used this test to verify the positive impact of real friends on our happiness:

Based on this rubric, I offer my own quiz, which you can take online or adapt from below to evaluate a relationship you might suspect of involving a frenemy. On the scale, a 1 means “very slightly or not at all” true, and a 5 means “extremely” true, to give a total between five and 25.

Although my test has not been validated in peer-reviewed research, I find it a handy way to assess relationships. When, after careful consideration, someone scores above about 20 for me, I judge that this must surely be a frenemy and let the relationship fade away. All of my longtime, true friends are at 10 or less. When someone comes in between these scores, I am watchful and wary. With a little thought and practice, you can figure out what the scores mean for you.

Becca Rashid and Arthur C. Brooks: How not to be your own worst enemy

The premise of this article is that you will know people who are frenemies to you, whom you should avoid when possible. But one more important question—a slightly uncomfortable one—remains. If you feel ambivalence toward someone, is that possibly because for them you represent a frenemy?

Ask yourself how some people in your life might assess you on the quiz, and why your score for them might be higher than it could be. Perhaps you have fallen into unhealthy patterns in a friendship; perhaps you bear some grudge or harbor resentments that are secretly poisoning your relationship with this person. You could even be mutual frenemies.

This year, beyond shedding the frenemies you can clearly identify, you might also resolve to be a better friend to others—and a real source of companionship, help, intimacy, alliance, validation, and security. If you want scholarly evidence, good research shows that this will raise your well-being. But you probably don’t need that to know that loving others is a unique source of joy.