Tom Brady is very, very good at his job.

But, according to New Yorkers, Boston-haters and one crucial federal agency, he is decidedly not terrific.

Indeed, on Thursday, no less an adversary than the United States Patent and Trademark Office pinned a big L on Mr. Brady, the superstar quarterback of the New England Patriots, when it declined his application to trademark the term “Tom Terrific” — a moniker long associated with Tom Seaver, the beloved New York Mets right-hander who helped pitch the team to a World Series championship in 1969.

The decision was blunt in its assessment of Mr. Brady’s case for the nickname, saying it could “falsely suggest a connection” with Mr. Seaver, who the office stressed was “uniquely and unmistakably” the only person associated with the nickname.

“Tom Seaver is so well known that consumers would presume a connection,” the office wrote.

Mr. Brady has been a mainstay in Boston for two decades, and his six Super Bowl wins have left some rabid Patriots fans calling him “Tom Terrific” as well, a nickname he has said he doesn’t like. Both he and his representatives insisted that their attempt to trademark the moniker was to prevent third parties from capitalizing on the unprotected nickname, both to his and Mr. Seaver’s detriment.