A motion for summary judgment is a judicial motion proper under Rule 11 of the Federal Rules of Civil Procedure (or Rule 661 of the Texas Rules of Civil Procedure). It is used by parties to a suit when, according to the pleading party, there are no genuine issues of material fact between the parties. The pleading party suggests that, despite the lack of material issues, the party is entitled to judgment as a matter of law - that is, even if the facts are undisputed, the other party has the law wrong, and must lose as a result.
Motions for Summary Judgment (or "MSJs") are used to save parties money in litigation, or to escalate costs on the opposing party.