A demurrer is a formal objection to the legal sufficiency of an opponent's pleading. It asks for a judgment in the demurring party's favor due to a failure to state a cause of action. A demurrer does not dispute the facts contained in the pleading, but the legal basis for the claim that a wrong requires a remedy.
Some demurrers argue that the complaint is vague or omits an essential element of fact. After a hearing, if the judge finds these errors, he/she will usually sustain the demurrer but allow the other party time to amend the complaint. If the complaint is not corrected, it will be dismissed. The Federal Rules of Civil Procedure and some states have replaced the demurrer with a motion to dismiss.