A tautology is a statement which is self evident through its terminology. It"s a definitive form of bad language usage, and is reviled by literary and media critics on a regular basis. Tautologies are by definition unnecessary statements, statements in which the meaning was already inferred. Tautologies are also bad conversational practice, frequently not tolerated in educated company. Some tautologies are unintentional, but rarely escape notice. Tautologies are sometimes used sarcastically as idioms.
Examples of Tautology: