Not so much a movie as roughly 100 minutes of quiet time, "Off Beat," now at area theaters, squanders the appealing romantic twosome of Judge Reinhold and Meg Tilly on a forced trifle about a New York library worker masquerading as a cop and discovering his true self while rehearsing with an amateur dance troupe.

Writer Mark Medoff's premise is certainly awkward, but once past that, the script has the makings of a moderately engaging romantic comedy, and one that is about as far from silly "Police Academy" slapstick as you can get. Unfortunately, the director is the distracted and oddly contemplative Michael Dinner ("Heaven Help Us"), whose dainty and hesitant approach undercuts the comedy elements and only occasionally delivers on the romance.

Reinhold, whose best known previous role was that of innocent Officer Billy, so grateful for the late supper sent by Eddie Murphy in "Beverly Hills Cop," is no leading man, true, but he and Tilly might have been able to carry it off if Dinner hadn't given the film such a hushed, pokey pace. Scenes that seem about to click are cut short, and the whole picture has a dithering, disjointed feel.

The plot is set in motion when Officer Abraham Washington (Cleavant Derricks, getting fat but an invaluable source of savvy energy here) asks his friend Joe Gower (Reinhold) to impersonate him at auditions for an amateur ballet company made up of off-duty cops. The fact that Washington is black and Gower white doesn't endanger the ruse, since Washington is the only member of the 22nd Precinct chosen to participate.

Gower is supposed to show up, klutz about, and be eliminated from the competition, but when he encounters Tilly as Officer Rachel Wareham, he has a love-at-first-sight situation on his hands. So he stays on.

Few of the comic possibilities of a layman trying to make it in a cop's world are explored. Even so, the film remains mildly diverting because Reinhold and Tilly are sweet together. Reinhold's natural underplayed passivity unfortunately has been made even more immobile under Dinner's direction, however, so there are moments in "Off Beat" when you could hear a pin drop. And wish someone would go ahead and drop one. It would be a relief.

Jacques d'Amboise, the ballet star, plays, rather embarrassingly, himself. Fred Gwynne is wasted in the tiny and unfunnily written role of the police commissioner; it's too bad, because when he shows up 15 minutes from the end of the film, you think he might actually liven the thing up. Amy Wright plays a fickle coworker at the library who previously spurned good ol' Joe but makes a surprise reappearance in his life.

Hanging around in a superfluous sidekick role is Penn Jillette, half of the wicked and daring comedy-magic duo Penn and Teller. Le grand Jillette looks as though he could slip into the kinds of roles that producers can't afford to hire John Candy for.

If either the cops-dancing element or the impersonating-an-officer element were played for nice solid chortles, "Off Beat" might have been able to get by, but Dinner isn't terribly interested in laughs, which is a problem for a comedy director. Reinhold and Tilly uphold a fetching mutual undercover charm, but "Off Beat" finally proves, even for them, too irreversibly off kilter.

Off Beat is rated PG for a smattering of strong language and a couple peeps of nudity.