10:15 AM PT -- Arthur Aidala, Rudy Giuliani's New York lawyer, tells TMZ ... "Of course, we are disappointed by it all, but we can't say we are surprised. The court has been very heavy handled with Mayor Giuliani from the inception of this matter. We are exploring any appellate options. Rudy and I traded some text messages -- he was not surprised at all – he felt there was no likelihood he would get a fair shake."

9:46 AM PT -- One of Rudy Giuliani's attorneys, L. Allyn Stockton, tells TMZ ... "If what New York has revoked his license for is similar to his conduct in Georgia, then they have revoked his license for merely representing a client zealously."

Rudy Giuliani has just lost his license to practice law in New York state.

The former NYC Mayor has been disbarred by a NY Appellate Court -- on recommendation from the State Bar -- after his license to practice law was suspended for making "demonstrably false and misleading statements" about the 2020 presidential election.

Giuliani was one of Donald Trump's fiercest and unwavering supporters as the former President made false claims of election fraud.

The court lays out a laundry list of false statements Giuliani publicly made since the 2020 election -- in all, there were 20 disciplinary charges based on those statements. One of the more colorful comments ... the Grievance Committee found Giuliani had falsely stated a vote was cast in Philadelphia in the name of deceased boxing champ Joe Frazier.

Giuliani eventually had to admit no such vote had been cast, and claimed he'd relied on a blogger's comment when he spewed the lie.

He further admits, in more than a dozen other instances, he regurgitated false information from various sources ... but insists he thought they were true when he said it. The court didn't buy that excuse.

When the State Bar suspended Giuliani's license, it determined his actions represented "an immediate threat" to the public and he also had "directly inflamed" tensions that led to the January 6th insurrection.

The former U.S. Attorney for the Southern District of New York has been criminally charged in Arizona for allegedly conspiring to overturn the 2020 election. He has pled not guilty.