What term other than "the faithful" would you suggest to refer to people who belong to some religion or participate in a religious event?

Members of religious denominations.

I’m faithful to my atheism. “Faithful” is a completely incorrect word to use in this context.

Maybe “godly”.

I think it’s appropriate, as our religion is faith-based.

Why not just name the religion that is the subject? I agree with your distaste of the use of the word.

Superstitionists.

“Faithful” may be an adjective on its own. When preceded by “the”, it is being used as a noun.
It is now commonly enough used that is generally accepted that way.

What about, believers, supporters, or followers?

Followers makes me think of Reverend Jimmy Jones.

The pious? The cultists? The Saints? (Commonly refer to religious leaders only) The children of X [insert name] religion. I believe the synonyms give a lot of alternatives. I can see that metaphor can be used as well. In Christianity, “the faithful” can be replaced with “sheep” and a pastor with “the shepherd”, and the “unfaithful” with “lost lamb”.

Believers.

Of course that brings to mind The Monkees
I’m a Believer

I like “the faithful” it suggests remaining true in a mild and unassuming way to something you deeply believe in. It is maybe overused and “the observant” could replace it but is a bit dry. “Followers“ maybe? or “adherents”?

Not everyone at a religious gathering could be called one of “the faithful” but the ceremony is predominantly for them and everyone there should at least have some respect for their beliefs even if they don’t share them. I would not be among “the faithful” myself but I would not object to being lumped in with the gathered masses. After all I had chosen to be at a place where there would be a call to faith.

Using terms like “believers” and “faithful” and such is allowing the religionists to improperly co-opt those terms for themselves. They’re redefining the terms for their benefit.

I am a firm believer in freedom of thought. I believe strongly in atheistic principles. Therefore I am a believer, but just not in what the religionists buy into.

If people are going to use the word “believer” it has to me modified with an adjective – “Christian Believers”, “Moslem Believers” and so on.

I would think faithful must by now qualify as a collective noun, and as such is probably about as neutral and accurate a word as you’re going to find.

If you’re just talking about the headline, “In Masterpiece Cakeshop, Justice Kennedy Strikes a Blow for the Freedom of Religion” would be more accurate. If we have to keep “dignity” in there, then “In Masterpiece Cakeshop, Justice Kennedy Strikes a Blow for the Dignity of the Religious” works just fine. The decision isn’t about any one religion, so there’s no point naming any particular group.

If you’re not just talking about the headline, I’m not sure there is a single term that is appropriate in all circumstances. Sometimes it is relevant to name the group or subgroup. The Pope isn’t going to welcome “the religious” because he’s not talking to everyone who is religious, but he’s not going to address his audience as “fellow Catholics” either because the Catholic Church still thinks of itself as the one true church representing all Christians.

@KNOWITALL “I think it’s appropriate, as our religion is faith-based.”

But it’s not the only faith-based religion, and the decision made by the court isn’t specifically about Christianity. So that doesn’t really constitute a reason.

The term you are looking for is pious.

@SavoirFaire I never said it was the only one and I was answering the Question, nothing to do with a court case. As a theist in a faith-based religion, it seems quite right.

“Faith” is a Christian thing. I think “faithful” is a rather poor and somewhat annoying choice of terms even for Christians. To me it implies an annoying flavor of Christianity, and is only a step or two better than calling them “saved”. It makes far less sense for other religions, let alone people who simply participate in spiritual activities.

I’d tend to just call them by whatever they call themselves, so words like “Christian” or “Buddhist”.

“Is our vocabulary so impoverished that there is no other term for people who practice or at least appear at a gathering for some religious purpose?”
– No.

“First of all, there’s no saying that all those thousands in the huge photos are faithful to anything. They might be curious tourists or skeptics or there just to bear witness to something. If you were in the crowd, would you be happy to be labeled as a “faithful”?”
– No, I’d be more-than-usually offended, and think whoever was saying that was being obnoxious and/or stupid.

If it’s not clear they’re all even members of the religion at all, they could be the attendees, or the audience.

“Second, “faithful” isn’t even a noun. It’s an adjective—a substantive adjective, in this case. Don’t we have a noun that would do?”
– That aspect doesn’t bother me, though I’d say it is part of the presumptive truthiness and universality of the Christian context, which is annoying. For instance, we can grammatically-enough refer to an army of zombies as “the dead”, or members of the GD as “the Dead”. There’s an implied but omitted noun after the adjective.)

“And third, it’s just tiresome to see the same term used over and over again in the same piece. The writers really seem to be unable to think of something else. Can we?”
– Sounds like the writers were particularly unimaginative and annoying. There are other annoying euphemisms for Christians, such as “the devoted” (which has the same problems, but is a different word).

I suspect “faithful” is used to conserve on words. “Religious adherents” is too much of a mouthful.

@KNOWITALL So you read the title and not the details. Got it.

Believers.
Theists.
Followers.
Members.

the throng
the crowd
the mob
the herd
the flock

I think it’s just an inoffensive term. These days, you have to choose your words carefully.

When I was a child, the word oriental was acceptable to refer to Asian people. Now it isn’t. I think it’s a PC thing….

I’d probably say “those in attendance” or “those gathered” blah blah blah. Unless, I knew the crowd was solely actual followers of the faith, then I might use a more religious term, but doubtful.

I guess I would even use witness, but the Christians have a different slant on that word, so I’d be careful.

Crowd and audience work too. In the right circumstance congregation is another word.

How about adherents ?

If you ask a religious person to explain why they believe, they invariably say that it is a matter of faith. The philosopher Kierkegaard coined the phrase leap of faith to describe it. Referring to believers as the faithful is most appropriate.

The congregation

I just refer to them as religionists.