Religion should be defined as the set of beliefs and practices that define who you are. Even an atheist is “religious”, because they also have a set of beliefs and practices that define who they are. Even an agnostic is “religious”, because they also have a set of beliefs and practices that define who they are.
I’d add to this that a fairly good number of people seem to use “religion” as a pejorative word for the set of beliefs and practices that those people don’t like.
Here I particularly have in mind one group, which has already been mentioned in this thread: those people who invoke Jesus and are also “religious” by any normal definition of the word

but seem to have chosen to use that word in a way that does violence to the language. Yes, there’s a germ of truth that we’re not to rely on external practices for our salvation, but their use of the word is a bit forced.
I particularly notice this use of the word because these people also tend to claim to have a high view of the Bible and sometimes keep asking, “where is that in the Bible?” So, where is the word “religion” (or “religious”) in the Bible? I’ve looked before because of my observation, and in common English translations, the word doesn’t seem to appear that much, and certainly there is no verse that tells us to use the word “religion” in the way that certain people use it.
We do find this:
I like how James puts it in the first chapter of his letter:
"Religion that God our Father accepts as pure and faultless is this: to look after orphans and widows in their distress and to keep oneself from being polluted by the world."
Usually that word is translated as “religion,” and I can’t help wondering if lots of young people and new Christians who’ve been told to believe that “religion” is a dirty word then read the book of James and get confused.
Sometimes, of course, confusion is caused by the shifting use of language, but this is more than an innocent, unintentional shift. Since this confusion is in a way self-inflicted–not inflicted by the young people and new Christians on themselves, of course, but by the wider group that has chosen to use the word “religion” in this way–I admit to being a bit amused at the thought, but twisting language does real harm.
I’ll even admit to wondering, because of that observation, if the people who started and propagated this use of the word “religion” were truly familiar with the Bible, or else they might’ve had more to say about the book of James.