“Christian” is a label/symbol, as are all English nouns. It does not derive its meaning from the Bible. It derives its meaning from the dictionary.
Kinda like “rapture”.
Both words most definitely have a meaning. Several, actually.
I believe it is precisely this reason some are moving away from the term. It has become a label and not a definition of who someone is. When our church went on a mission trip to the Portland area to help one of our partner churches, we discovered that they do not use the term "Christian" when asking someone about their faith...or when describing their own faith. Instead...they refer to themselves as "Followers of Christ," which is much more clear on where you stand.
Many people in this country call themselves Christians...but embrace doctrines that are not orthodox and deny doctrines that are (Jesus as "The Way" for instance).