1a. A minority Christian doctrine that rejects science, promotes stupidity, bullshit, and will do anything irrational.
1b. It is a hypocritical sect that claims to not believe in magic, but instead they promote their own form of magic.
1c. Basically, it's the same thing as Holocaust denial, that is, they both promote something irrational, childish, and unsubstantiated over something supported by incredible amounts of evidence and years of hard work, and both degrade a group of people (creationism degrades scientists; Holocaust denial degrades Jews).
Creationism is an excuse for being stupid.