It was a bad sign when the Supreme Court relied on the dictionary as the main authority in a recent ruling that made it harder for whistle-blowers to hold government contractors accountable for fraud.

The case, Schindler Elevator Corp. v. United States ex rel. Kirk, involves the federal False Claims Act, which allows a private party to bring an antifraud lawsuit on behalf of the federal government and receive part of the damages. The law bars such suits, however, if the allegations are based on publicly disclosed information, like a government report, investigation, criminal hearing or a news report. The ban exists to prevent superfluous private actions when the government can pursue a lawsuit.

In the current case, the plaintiff sued his former employer, Schindler Elevator, charging that it failed to comply with federal contracting rules on employing veterans. He based part of his case on written information from the Department of Labor, obtained through a Freedom of Information Act request.

The court’s ruling turns on whether that response is a publicly disclosed “report.” Justice Clarence Thomas, writing for the 5-to-3 majority, finds that Webster’s Third New International Dictionary all but settles the matter: it defines “report” as “something that gives information.” The broad meaning there, he says, squares with the “broad scope” of the prohibition against lawsuits based on public disclosures. His view could rule out most antifraud lawsuits based on FOIA requests.