A lot of guys don't know the phrase "gaslighting," but it's something that many women are familiar with. The term, which comes from the play (and subsequent film) "Gaslight," describes a form of mental abuse and manipulation that can be progressive and subtle, but will eventually make a person doubt their perception of reality.

While men and women can be participants on both sides, it's most commonly (and perhaps casually) used to describe male behavior, often in romantic relationships. There seem to be shades of gray associated with the word -- from the mildly insensitive to the legitimately harmful -- so MTV News called up Dr. George Simon, a clinical psychologist and author who specializes in manipulation, for his insight on the topic.

Simon made it clear that women seem to refer more to the concept than men, and even when guys are accused of it, they don't always know what it means. Since most of the information online about gaslighting is aimed at educating women, here's what guys need to know about it.

What is gaslighting exactly?

"Gaslighting refers to a specific, deliberate, and extremely abusive manipulation tactic -- make the person who's getting a clue about your true character, your true intentions or your nefarious behavior believe they're crazy for thinking or suspecting as they do," Dr. Simon clarified.

True gaslighting is somewhat rare. However, Simon said that it's possible to cause a "gaslighting effect" without a malicious intent, which may explain why the phrase is so colloquially used.

You can produce this effect without realizing it

If you've been accused of gaslighting, and don't consider yourself a manipulative person, it's easy to get defensive about being lumped into a mental abuse category. As Dr. Simon said, "Confident, highly-opinionated and forceful individuals can produce a 'gaslighting effect' on a 'weaker' individual without even half-trying."

Although this unintentional behavior can be viewed as a form of gaslighting, he noted that that's not exactly what the term means. Still, over time it may have similar consequences, even without the same abusive intent. Both concepts overlap and differ, but neither is good for the other person.

Here's an example: Do you often question a story that she said happened, or belittle her reaction to it?

When she told you about a conflict at work or with her friends, you may have offhandedly used the phrase "it's in your head," but you may not realize how dismissive that can sound. When someone you care about comes to you with an issue, invalidating it is never the right solution.

If your partner is blaming you for a problem, you should be able to assert your side of things without making her doubt her perception of reality. If she's always giving you the benefit of the doubt, consider returning the favor.

"Crazy" is not the best word to throw around

Girls can be just as guilty as guys of throwing this little c-word around, but we all need to stop. According to Dr. Simon, it can be particularly harmful when the person being written off as crazy is sensitive to self-doubt. You may not be responsible for your partner's mental health, but you are accountable for what you say. If you tell someone they're crazy enough, they might act like it ... and there's nothing casual about a word that can do that.

Calling a woman "irrational" or "oversensitive" isn't good for you either

"Irrational," "high-maintenance" and "too sensitive" are all replacements for the word "crazy," and have the same negative impact. As Dr. Simon pointed out, it can be harmful to both parties involved. "The woman becomes even less secure, and the man reinforces a pattern of being insensitive to the vulnerabilities of others, a dangerous thing when it comes to character development," he said.

If you have a legitimate problem with how your significant other is acting, try to address that specifically without bringing these broader character judgements into it.

There is no correlation between attractiveness and mental instability

Despite what Barney Stinson (and this guy) suggest, there is no real correlation between how hot a person is and how crazy they are. Actually recent research has found that positive personality traits like kindness are more likely to increase perceived attractiveness, but unfortunately there's no such thing as a "hot/kindness matrix."

It doesn't matter if she's on her period, so don't ask

OK, we can all agree that PMS is real and can impact a woman's mood, but to act like it's a significant enough factor to disqualify her feelings and opinions is just as bad as calling her crazy. Not only is this unfair, it's super hypocritical. Men can experience mood shifts based on hormonal cycles (mostly falling testosterone levels throughout the day -- it's known as Irritable Male Syndrome), and we won't ask you about it if you agree to stop asking about ours.

Women are not the only victims of gaslighting -- but historically, they've been more vulnerable to it

Men, women and children can all be victimized by gaslighting, but women have been more likely to experience it in the past. That may be changing as women become more empowered, but the shift isn't by any means complete. "Given our cultural history and its impact on women and their sense of self-confidence and worth, there's a long way to go yet," Dr. Simon said.

Gaslighting can take a serious toll on a person's wellbeing

"In the short-term, the consequence [of gaslighting] is getting manipulated," Dr. Simon said. "Long term, a person's doubts only increase and their self-esteem and self-image take a big hit."

Falling into the "gaslighting effect" doesn't necessarily make you the bad guy -- and you can change it

Deliberate gaslighters are aware of the harm it does, whereas those unintentionally producing the same effect may not be aware of it. As Dr. Simon advised, by increasing your awareness of what such dismissive behavior can do to someone you care about, you'll be less likely to take part in it.

So if you care about someone and recognize this toxic dynamic, do your best to address it -- for the good of everyone involved.