Generally considered the branch of theology that is concerned with defending or proving the truth of Christian doctrines.
The late Catholic apologist, the Bishop Fulton Sheen, argued eloquently for the practice with the following rationale: “The Church discourages bad thinking, for a bad thought set loose is more dangerous than a wild man. Thinkers live; toilers die in a day. To kill one bad thought may mean the salvation of ten thousand thinkers.”
Some argue the Epistles themselves are fervent examples of Christian apologetics. I agree to some extent, but only so long as you remember the audience for Paul, James, Peter, John, and the author of Hebrews: the Christian Church and its members. Today apologetics is more seen as arguing with unbelievers about the legitimate truth of the faith. This is the approach I am not so sure about.
Paul tells the Corinthians that “And when I came to you, brethren, I did not come with superiority of speech or of wisdom, proclaiming to you the testimony of God. For I determined to know nothing among you except Jesus Christ, and Him crucified.” There is more to this and maybe it is deserving of a detailed post, but this concern has been finding purchase in me for some time.