The American Bar Association commissioned the report but then refused to publish it, citing "the risk of the A.B.A. being sued by Mr. Trump," the Times reported.
"Donald J. Trump is a libel bully. Like most bullies, he's also a loser, to borrow from Trump's vocabulary," First Amendment lawyer Susan E. Seager wrote in the spiked report, which ultimately saw the light of day when it was published Friday on the website of the Media Law Resource Center.
James Dimos, deputy executive director of the ABA, objected to "inflammatory language" in the report, according to the Times.
"While we do not believe that such a lawsuit has merit, it is certainly reasonable to attempt to reduce such a likelihood by removing inflammatory language that is unnecessary to further the article’s thesis," Dimos wrote in an internal email quoted in the report.
David J. Bodney, a former chair of the ABA's media law committee, told the Times that he found it "more than a little ironic" that the association would stifle a report about Trump's record of using litigation to silence his critics.
Charles D. Tobin, another former chairman, told the Times that the association's actions were "colossally inappropriate."
Dimos did not respond to the Times' request for comment.
ABA spokeswoman Carol Stevens told the Times that the association had only asked for "minor edits" to the report, and denied that fear of litigation had been a factor.
In response to Trump's threat, New York Times assistant general counsel David McCraw wrote that the Times would "welcome the opportunity to have a court set him straight."
No lawsuit has yet materialized.