At the very beginning of a lawsuit, a defendant may choose to file a motion to dismiss instead of simply answering the complaint.
A motion to dismiss will only be allowed if there is a clear legal issue that is obvious from the face of a complaint. This is because the law favors full adjudication of disputes, after an opportunity for discovery.
Examples of clear legal issues include statute of limitations, failure to allege a fact that is essential to proving the plaintiff's claim, or failure to do something the law requires the plaintiff to do before filing suit, like going to MCAD or EEOC first with a discrimination claim.
On a motion to dismiss, the court is required to believe the factual allegations in the complaint. This means a motion to dismiss is not the time to challenge those factual allegations, or submit contrary evidence. For this reason, if you are a defendant, your attorneys may advise you not to invest the money in a motion to dismiss unless there is a clear legal issue.
Learn more here about what to expect as a defendant in a civil lawsuit.