Christian

A Christian is anyone who realizes that they are not good, and subsequently fully trusts in Jesus Christ for the forgiveness of all they've done wrong and for their assurance of eternity in Heaven with God. Once someone realizes how much God loves them in providing a way for them to be forgiven from all the wrong they've done, and trusts Christ to forgive them from their sins and rescue them from eternal separation from Him and torment in Hell, he or she then strives to become more like Christ as their life goes on. Doing so should be a thankful response to the grace that they have been shown in being forgiven by God and through God, and not as a means for obtaining salvation by their own merit. Even the very ability or power to do anything pleasing to God comes from God (namely the Holy Spirit. Don't worry, we'll get to defining the Trinity)! It is impossible for mankind to be "good enough". We need the perfection of Christ to be applied to our lives in order to have a personal relationship with, or be in the presence of, a Holy God. This is what a person who claims to be a Christian is affirming whether they realize it or not.

The word Christian literally means "follower of Christ" or "little Christ".

I feel like there's way more the say here, but I'll leave it at this for now.

Two additions based off your responses:

1. To be a Christian one must acknowledge the deity of Jesus Christ (know that He was, is, and always will be God).

2. To be a Christian one must also believe that Jesus Christ was resurrected bodily (He came back to life after being dead for 3 days). He was confirmed dead by a professional executioner, was buried for 3 days, and after He came back to life more than 512 people saw Him in person before He ascended to heaven. That is a lot of people to back up a claim!