NYC- He may not be a model neighbor, but a middle-aged Manhattan man with a thing for younger women draws the line at implications that he beds underage beauties.

And a judge apparently agrees – giving the green light to a defamation suit by model manager and attorney William Unroch, who sued a neighbor in his West End Ave. co-op after she allegedly told other residents he shacks up with underage girls.

“To be living with a 22-year-old isn’t a crime – besides she’s turning 23 soon,” Unroch, 56, said of his girlfriend, Avarelle Cordero.

The feud broke out during Unroch’s bruising run for a spot on the co-op board of Lincoln Towers last May. Downstairs neighbor Carol Monderer allegedly dug up Unroch’s 1982 grand larceny conviction and labeled him a pornographer for posting links to raunchy pictures on his Web site.

Manhattan Supreme Court Justice Rolando Acosta said he had no problem with Monderer labeling Unroch a “pornographer” – in part, because his modeling firm’s Web site links to photos of topless women.

But Acosta said Monderer may have crossed the line when she “clearly implied [he] was sexually involved with minors.”

He ruled a jury should be allowed to decide if the statement was “reckless,” given that Unroch’s girlfriend “was 22.”

An attorney for Monderer, a 53-year-old mother of three, declined to comment. But in court papers, Monderer said Unroch had “abused the legal system by bringing this frivolous lawsuit.”

She also took issue with a section of Unroch’s Web site, in which he advises would-be models to not wear engagement rings to meetings with talent agents – and suggests that working as “strippers,” “go-go dancers” and “unlicensed masseuses” can help pay the rent.

Unroch countered that his advice is hardly X-rated.

“You could read ‘Dear Abby’ … and get more racy advice,” he said in court papers.