The word apologist comes from the word *apologia *(“defense”) and describes someone who defends and explains a particular proposition. A Catholic apologist defends and explains the Catholic faith. An apologist is a teacher, as is a catechist, but the apologist is a teacher of a special sort:
The apologist is distinguished from a catechist in that the catechist is purely a teacher of the Christian faith while an apologist is a teacher who seeks to persuade someone that the Christian faith is reasonable. In other words, a catechist teaches the Christian faith to expand the knowledge of a sympathetic student while an apologist seeks to teach the faith to someone who is not necessarily ready to believe it and may be actively opposed to believing it.
The role of the apologist is not analogous to that of an engineer because, strictly speaking, it is not an apologist’s job to apply the principles of the faith to everyday moral dilemmas in like manner to how an engineer applies science to everyday problems. That is more properly the role of a spiritual director. That said, on a practical level, apologists often get those kind of questions anyway and must be prepared to handle them.
Does Catholicism have too many do’s and don’ts?
Toolbox Apologetics by Jimmy Akin