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There may be seven words you can never say on television, but only five are needed to describe George Carlin. At least according to Robin Williams.

"He was one funny motherf--ker," Williams said of his legendarily caustic comedic forebear, who died of heart failure Sunday evening at the age of 71.

"George Carlin was the living embodiment of the First Amendment. In the traditions of Mark Twain and Jonathan Swift, he dealt with the insanity of the world with the one-two punch of humor and honesty with no apologies," added Williams.

"He was one of the greats," Ben Stiller said in a more censor-friendly statement, "and he will be missed. [He] was a hugely influential force in stand-up comedy. He had an amazing mind, and his humor was brave and always challenging us to look at ourselves and question our belief systems, while being incredibly entertaining."

Kevin Smith, who frequently cast Carlin in films and who gave the taboo breaker his last live-action big-screen role in 2004's Jersey Girl, reacted to news of the death on his official website this morning.

"Dammit. My favorite memory of Carlin is sitting in the audience at one of his Vegas shows as he did his 'People I Can Do Without' routine," Smith wrote. "When he got to 'guys over the age of 10 who wear their baseball hats backwards,' he tossed in 'Kevin, you're exempt from this.'

"Changed my sense of humor forever. Sixteen years later, I was happy to have met the man, let alone worked with him. Honestly, I was lucky to have known him at all."

Jay Leno also paid tribute to his fallen friend, who broke onto the national scene back in the 1960s as a hippy-dippy weatherman on Johnny Carson's Tonight Show.

"If there was ever a comedian who was a voice of their generation, it was George Carlin," Leno said. "Before George, comedians aspired to put on nice suits and perform in Las Vegas. George rebelled against that life.

"His comedy took on privilege and elitism, even railing against the game of golf. He never lost that fire. May he continue to inspire young people never to accept the status quo."

Judd Apatow gave props to Carlin's influence over today's class of cutups.

"Nobody was funnier than George Carlin," he said. "I spent half my childhood in my room listening to his records experiencing pure joy. And he was as kind as he was funny."

Saturday Night Live mastermind Lorne Michaels was also in mourning for the comic genius who served as the first-ever host of SNL, albeit one who later admitted to having been on cocaine for the duration of his appearance.

"You never forget the people who were there at the beginning," Michaels said. "George Carlin helped give Saturday Night Live its start as our first host. He was gracious, fearless and, most important of all, funny."

NBC will rebroadcast the 1975 inaugural episode of SNL, featuing three Carlin monologues, in its entirety  this weekend.

HBO, which produced 14 Carlin-fronted comedy specials, also issued a statement on the funnyman's death.

"Because HBO has had such a long and close relationship with George Carlin, his passing is like losing one of our own," the cable net said in a statement.

"No performer was more important to helping our network define itself in its early years. And no performer was more committed to the ideal of freedom of speech, a principle he embodied for the 50 years he performed with his trademark wit.

"We will miss his humor and his righteous comic anger, and we will simply miss him."

Jerry Seinfeld, meanwhile, is penning a eulogy to Carlin for tomorrow's New York Times. He's also set to speak about his comedic forebear on tonight's Larry King Live.

(Originally published June 23, 2008 at 1:53 p.m. PT.)