Suppressed Evidence To ignore certain facts that destroy your argument.
First example: In arguing against the fossil record, creationists often cite the "Great Flood." The water level began to rise so the "more advanced" creatures would move to higher ground, but the "more primitive" creatures would not. This is, it is explained, why you find less complex creatures further "down" in the fossil record, and human fossils near the "top." This falls apart when you consider marine organisms, who would have considered the Great Flood a "good thing." In addition there have been many great floods over time.
Second example: Creationists note that there are no transitional fossils which demonstrate the evolutionary process, since the fossil record is incomplete. They also argue that there are no fossils with "legs or arms that are half grown out". However, there are many examples of transitional fossils. Archaeopteryx (at right) shows both bird-like features and dinosaur-like features. "Lucy" (at left), an Australopithecus afarensis, is one of man's most ancient ancestors and represents a "missing link" that is no longer missing.