Ya gotta be gullible, arrogant, easily manipulated, and deny science and facts.
Then they give you a t-shirt at level eight.

I'm of two minds on this.

On the one hand, I think that someone is a Christian if they believe that Christ is - at least potentially - their savior. Behavior is irrelevant to the question - we have good Christians and bad Christians, and the good may wish to disown the bad, but I call bullshit on that.

On the other hand, I am very skeptical that any of them actually, truly believe that Christ will - or even can - save them. At least not with the eternal life part.

Best spoken with Midlothian accent: "The No True Scotsman fallacy!"

This is a very good question because Jesus was also not a Christian. Let's also look at churches and the alter scene with prayers and wailing and Jesus ending up inside you. OMG you are saved ! The problem is that there are no scenes like this in the bible.

There isn't any such thing as an official, objective definition of what makes a person ANY religion. Subjective definitions abound, all claiming to be the correct one. Good luck!

Unfortunately,Christians self identify. That means they don't have to follow any of the teachings, but just identify as "Christians". Because there are so many various sects, there is no set of qualities one can use to measure to determine Christianity.

Some think all you hav eot do is simply believe in Jesus and you are saved, and it doesnt' matter what you actually do or say in your life.

First thought was who cares but then I had a mind shift thing happen as I explain:

I tend to just accept people for who they claim they are - it's when actions do not align with their words I take a closer look. Example
There is a person I know, female, very religious, reads the bible daily. Pre COVID she hosted a bible study group and when trump was placed in the WH tried to get the members of the group to sign some petition. It caused the group to fall apart as many felt it crossed the line of separation of church and state.
She and her husband believe a pretty rigid idea of Christianity PLUS everything said on fox TV is the God's honest truth and fact. Outside of that she is a nice person, tends to seek out and help some of the more disabled or less mobile residents in the complex and makes a GREAT Caesar Salad for potlucks.
It was pointed out to me one day that there is a method to her help - it's more about gaining brownie points to get into heaven than from a real altruistic stance.
I changed my view to EXcellent question/thought. I never gave that view much thought, though recognizing the hypocrisy was almost always easy, their true motive may be harder to discern. Ultimately each person seems to decide what it means to be christian - so which came first the religion or the being christian?

To answer your questions, you would have to get inside of the mind of the person claiming to be a Christian.

There isn't one, and there never has been any definitive definition of what Christian means, or even Christianity, over 2,000 years. It's whatever people want to say it is. That's the simple truth of it. Like any meme, it can evolve and mutate any way it wants. One might think that some basic criteria might apply, like belief in the Abrahamic God and son of that God. But no, there are some post-Christian churches who don't believe in a personal God, but rather a big cosmic energy thingy , and Jesus is not a real historical figure but an inspirational mythical whatnot, and yes they call themselves post Christians, or something meaning that. Ultimately when something can mean anything you like, in truth it means nothing or whatever you want it to be. Christianity is based on a God saviour meme that has been knocking around human religious history for something like 10,000 years or longer. It just keeps evolving and mutating, as it has for millennia. What makes a Christian a Christian? Anything you want.

One of the letter-writers(James?) of the New Testament scolded the "believers" of a town, saying their behavior was deplorable and that their pagan neighbor's "christian" actions were such that they would be in heaven before the Christians would.
Seems that James thought is that you don't have to believe, but you must act like you believe.

In my mind a person decides whether or not they will believe in and follow the tenets and practices of whatever religion they decide they wish to belong to. So generally speaking I'd assume a person that follows the teachings of Christ would be one. Sadly that would rule out a number of those who claim it but don't actually practice it.

To be honest, I don't really care.
The way people treat others is much more important to me than some label.
I know both some great, and shit people that will call themselves 'Christian', and the same goes for non-believers I know.

FB randos are the ultimate authority. I know, I went on FB and asked a poll on that. It seems that Twitter also has some pretty authoritative persons on nearly all subjects.

That's a question they can't even answer themselves, otherwise there wouldn't be so many sects. So what chance would we have and why would we bother to attempt it?

Someone with an absolutely lovely P-Touch printer, hey by brother exclusively. They can stick labels all over anything they want.

I've been called Christian because my actions caused someone to make that assumption. When I replied that I'm not Christian, I was informed that yes I am, whether I believe it or not, because I do good things, and being Christian just means being a good person. Huh!

Another friend went crying to her pastor regarding me. I had told her I was agnostic, and that really bothered her. Before and also after that chat, I would do nice things for her and her family, just being neighborly, because I'm human and that's what humans do. She couldn't understand how I could be a nice person, yet not believe in God. What bothered her most is that according to what her pastor said, I would not go to heaven, but to hell, and she couldn't bear that. I told her I didn't believe in either of those either, so don't worry about me. Just enjoy life.

Then there are people who call themselves Christian, but behave abominably, yet we are asked to take them at their word. Those would be fake Christians, I guess.

So gauging from my experiences, I would say that a person isn't Christian, unless they try to be a good person, but a good person isn't necessarily Christian. Calling oneself Christian, doesn't make it so.

Who the fuck cares?!

As with many things, people are left to identify themselves as being a member of a group or having a particular characteristic.

Sadly, any person can identify himself as Christian and thus collect all the social benefits that go with it. There isn't any requirement for them to do any particular thing, except convince the other suckers.

Well, it depends on one’s definition and there is no perfect dictionary. I used to think “Christian” = (a)“Anyone going to heaven” or, I thought equivalently, “Anyone not going to hell.” But now, according to (a) I suspect no one is a Christian and no one has ever been, while according to I propose everyone is a Christian and everyone has always been!

Christ?

There is a whole bunch of vicars/priests in the UK who have got themselves together under the Title ' Sea of faith '( research Don Cupit) I am not sure how far it reaches in America and beyond but there may be an organization with a separate name. The reason for their formation is that they have all lost their faith -particularly accepting Jesus as LORD . Many of them retain their employment of spreading Christianity OR have help from the organization to find alternative employment. Ask them for their reasons for joining SOF and what is the tipping point for being dismissed from the church.

I think a true Christian is someonewho doesn't cherry pick the bible. They are proper fundamentalists because of that. They don't trust science, believe the end is near, women should obey men, etc..

Are you trying to get a precise definition so you can counter the fallacy of the "true Scotsman"?
If it is the case, it is impossible, because the "true Christian" is vague enough to be able to support the people in power.

A sinful person can only be judged by god if it is in power, but a much less sinful person can be ostracized if it is against the established power.

If you want to be strictly legalist, any person who is baptized in a self-defined Christian organization is Christian, and will only not be christian anymore if excommunicated or if it declares apostasy formally, and by formally i mean a formal letter to the church in which you are baptized, what will lead to excommunication in most of the churches.

The quality of this faith is not taken into account on this, a bad christian is still a christian.
Any non excommunicated or non apostate is still a christian that is deviating from the path (surprise fake atheists, you are still counted as members of the bronze age, goat fuckers club).

You get to be who you want to be when it comes to philosophical stuff. All kinds of self proclaimed christians don't follow any christian teachings. You might not be a good christian but you can be one if you want. There are so many sects of christianity that no one knows the difference. I can say I'm a donor even if I've never donated anything. Someone with a different definition of christianity might differ with how you live your life or your beliefs and they may say you're not a christian but they aren't the arbiters of who you are. You can say you're superman if you want and jump off tall buildings--it may get you hospitalized both medically and psychologically but that's the price you pay.