Yes.
Anyone, no matter how bad of a person they may be, can call themselves a Christian. Anyone can call themselves anything they want. That doesn't make it true.
Also, anyone can believe in Christ and still not be "saved." In The Bible (James 2:19), it says, "You believe that there is one God. Good! Even the demons believe that-and shudder."
As for being a true believer and follower of Jesus Christ, I do not believe that someone who repeatedly and deliberately disobeys the commands of the Bible can truly and honestly call themselves a Christian.
Jehovah's Witnesses DO call themselves Christian. They acknowledge they are a Christian religion and are baptised in Christ's name. Most secular authorities recognise Jehovah's Witnesses as a Christian denomination.
The sign of the cross.
You can call him/her, Non-Christian.
The people who call themselves Christian.
Now, worldwide with over 2 billions people who call themselves Christian. The 'most' Christian nation is the U.S.A..
You can call them George Costanza.
Jehovah's Witnesses DO call themselves Christian. They acknowledge they are a Christian religion and are baptised in Christ's name. Most secular authorities recognise Jehovah's Witnesses as a Christian denomination.
Protestants.
Roman Catholic AnswerNothing separates Catholics from the Christian religion as Catholics are the Christian religion started by Our Blessed Lord. The Orthodox Church is also Christian, but in schism. All other ecclesial communities that call themselves Christian are only Christian insofar as they have a valid baptism and believe in the Nicene Creed in its traditional interpretation. To one extent or another they are all heretical interpretations of Christianity.
Because they believe in the basic fundamentals of the Bible.
The word "Puritan" was often used to characterize the Protestant group as extremists similar to the Cathari of France. They did not call themselves Puritans, but their intent was to "purify" the Christian religious practices.
A person who lies to themselves or twists the truth is called a 'denier.'