Just to clear up a few discrepancies in terminology:
There are two kinds of masons/Masons:
The Mason who is a member of a club, who goes to meetings, performs rituals, etc.
The mason who works with bricks and mortar.
A Mason isn't necessarily a mason and a mason isn't necessarily a Mason.
A Mason has no business telling a mason, "You're No True Mason," and a mason has no business telling a Mason, "You're no true mason."
Similarly, there are Christians who belong to a chapter of the Christian club. One Christian has no business telling another Christian that his chapter is unaccredited.
There are also christians who work with the bricks and mortar of christianity on a daily basis.
Christians have no business telling christians that they're No True Christians, even if they're not official members of the club. And christians have no business telling Christians that they're no true christians even if they don't work with the bricks and mortar of christianity.
(To further confuse the issue, I capitalize both types of Christian out of respect.)
I'd say they are, very simply, believing and following Jesus.
Suppose you're driving down the highway (having missed the bus to New Jersey) and a police officer flags you down and tells you the road is closed ahead. There's a bridge out. You have to take a detour.
You say, "Okay, I believe you," and you continue driving down the road, repeating to yourself, "Yup, I sure do believe that police officer," until you go sailing into the Delaware River.
Following a belief means doing something about it, not just "believing" it.
I would describe a Christian as someone who believes the Old Roman Creed. This is from the second century and would be the earliest compiled statement of faith.(What you needed to believe to be a Christian then, NOT what you need to believe to be a Christian now, according to some people)
The Old Roman Creed I believe in God the Father Almighty. And in Jesus Christ his only Son our Lord, who was born of the Holy Spirit and the Virgin Mary; crucified under Pontius Pilate and buried; the third day he rose from the dead; he ascended into heaven, and sits at the right hand of the Father, from thence he shall come to judge the quick and the dead. And in the Holy Spirit; the holy Church; the forgiveness of sins; the resurrection of the flesh
Note that this creed says NOT a single thing about scripture or it being literally correct or true or it being "the word of God". Not surprising since The Old Roman Creed predates the "bible" by about 150 years, but I would think if they thought old books important they would have mentioned them in a statement of faith.
Early Christians had no "bible" but they were still Christians.
P.S. Does this creed say Jesus Christ= God, or does it say Jesus Christ= the only son of God?