If a judge grants a motion to dismiss, he or she is saying that the law does not recognize a legal claim for the facts stated by the complaining party. In a motion to dismiss, the defendant asserts that the complaint or counterclaim does not amount to a legally valid claim even if the factual allegations contained in the complaint or counterclaim are accepted as true.
Usually, a motion to dismiss attacks a complaint as missing one or more required elements of a claim. For example, in a negligence cause of action, the plaintiff must allege that: 1) the defendant owed a duty to the plaintiff; 2) the defendant breached the duty; 3) the breach caused plaintiff injury; and 4) the plaintiff suffered damage. A defendant could move to dismiss by saying that the complaint failed to plead one or more of these essential elements.
Motions to dismiss are decided by the judge rather than the jury. If a judge grants a motion to dismiss, he or she may grant it "with prejudice" or "without prejudice." With prejudice means the plaintiff cannot file another complaint attempting to fix the insufficiencies of the previous complaint. If the motion to dismiss is granted without prejudice, then the plaintiff has permission to correct errors by rewriting the complaint and filing an amended complaint. Motions to dismiss granted with prejudice are rare and reserved for when the judge determines a plaintiff cannot cure or fix the complaint by rewriting or amending it. Because leave to amend is so liberally granted, a motion to dismiss usually is only filed if a plaintiff refuses to repair a fatally deficient complaint or if the complaint cannot ever be supported by law. Many courts will fine or sanction a party who files a motion to dismiss for improper motive, for example, to harass or intimidate the opposing party.