This refers to an attorney asking a judge to punish another attorney or party pursuant to Rule 11 of the Federal Rules of Civil Procedure.  You can find the text of Rule 11 and some notes on it here.

When an attorney (or an unrepresented party) submits a complaint, defense, memorandum of law, or other written submission to the court he is certifying that the document (i) is not being submitted for an improper purpose such as to harass someone; (ii) the legal arguments have a basis under existing law or there is a good-faith basis to change the law or create new law; (iii) the facts are supported by evidence or will be supported by evidence; and (iv) denials of any facts are supported by evidence or will be supported by evidence.

For example, let’s say a person sues a company for unlawfully firing him.  But there is no dispute that this person never worked for the company.      The parties will first meet to discuss the issue themselves.  Perhaps this was an honest mistake and the employee sued the wrong company.   If they cannot resolve the issue, the company’s lawyer might move for sanctions – – that is, he will ask the judge to punish the plaintiff suing the company and/or the plaintiff’s attorney pursuant to Rule 11.  Among other things, in this case, the sanctioned party might have to pay the defendant’s attorney fees.