Apologetics is the discipline of defending a position using reason.  The word is so tied to the defense of Christianity that “Christian apologetics” is almost redundant.  An apologetic is a specific argument (the Design Argument or Pascal’s Wager, for example).
Though “apologetics” has its origin in common with the word “apology,” the apologist does not apologize.  The original Greek work apologia meant to make a spoken defense, such as you’d give if you were the defendant in court.
A Christian could argue for Christianity in an emotional way, but that wouldn’t be apologetics.  These nonapologetic claims might be “Christianity makes me feel good” or “I just like the worldview” or “You’ll love the community.”
Counter-apologetics uses reason to rebut specific Christian apologetic arguments.
Photo credit: Wikimedia
Related posts:

• See all the definitions in the Cross Examined Glossary.

Related links:

• “Apologetics” at Iron Chariots Wiki.
• “Apologetics” at RationalWiki.