apologetics |əˌpäləˈjetiks|
Apologetics is the defense of the Christian faith.  "Apologetics" is a term that comes from the Greek work apologia that means simply, 'defense.' It is not to apologize for what one believes or to apologize if someone's offended at the proclamation of the Lord Jesus Christ, but to make a defense for it. In Peter's first letter to the churches of Asian Minor, he wrote these words:
"...in your hearts set apart Christ the Lord as holy, always being prepared to make a defense [apologia] to anyone who asks you for the reason for the hope that is in you...." (1 Peter 3:15)
Specifically, I believe Christian apologetics is not a defense of mere theism, but a defense of the proclamation that Jesus is Lord--the King of kings and the Lord of lords. Believers are called to make a defense of the Gospel of Jesus Christ, which is in part a proclamation of His lordship. We are not called to make a defense of personal opinions or personal preferences on religious topics, but rather "to set apart Christ the Lord" and to give an answer for that.   That is, we are devoted to His Lordship.

Christianity at its basic level is just this proclamation.   This confession, says the late missionary to India, Lesslie Newbigin,
“...is distinguished in that it is a commitment to a belief about the meaning of the whole of human experience in its entirety--namely, the belief that this meaning is to be found in the person of Jesus Christ, incarnate, crucified, risen, and destined to reign over all things.”