In “H.M.S. Pinafore,” W.S. Gilbert made a pretty good joke about confusion between “orphan” and “often.” This new thriller brings it to mind because its premise about an evil, homicidal child has gotten really old over the last half-century. It was fresh back in 1956, when “The Bad Seed” came out, but after “The Good Son” and “Joshua”—not to mention “The Omen” and its supernatural ilk, it’s been played to death. Good heavens, poor Vera Farmiga is being put through her paces as the distraught mother for a second time, after “Joshua.” At least she’s got a girl in this version.

But a girl of a very peculiar sort, as Farmiga’s character, a Connecticut housewife named Kate Coleman, discovers when she and her husband John (Peter Sarsgard) bring Esther (Isabelle Fuhrman), a nine-year old Russian refugee whose previous American stepparents had died in a house fire, home from a Catholic orphanage. Esther’s a peculiarly old-fashioned kid whose odd ways have different reactions on the two Coleman children. Danny (Jimmy Bennett) resents her, while his little deaf sister Max (Aryana Engineer) bonds with her immediately.

It’s clear why adoption agencies have been protesting “Orphan” so vociferously, because even apart from the basic plot in which Esther quickly shows herself to be not just a manipulative interloper dividing the Coleman family unit but a murderous maniac to boot, the very process that initiates the narrative is borderline absurd. It’s not just that nothing’s known about Esther’s background, apart from the fate of her previous American parents (which serves as the basis for a last-act twist that’s bound to elicit derisive hoots from the audience). It’s that Sister Abigail (CCH Pounder), the nun who runs the orphanage, apparently has done no significant checks on the Colemans’ suitability. They’ve only recently lost their third child, whom they call Jessica, to a miscarriage (an event portrayed in a tawdry, grotesque prologue that turns out, of course, to be a nightmare)—a tragedy that’s sent Kate into such an emotional tailspin that she’s in therapy (Margo Martindale plays her shrink). She’s also lost her job as a music professor at Yale (!) and is a recovering alcoholic.

But I digress. The problem with “Orphan” isn’t merely that the movie is idiotic–it’s that it’s also sleazy, formulaic and repellant. All the adults are dumb—especially John, who’s a gullible nitwit (Sarsgard is just too intelligent an actor to be playing such a dolt), Sister Abigail (who seems to suspect problems are afoot even before the adoption but goes ahead with it anyway) and the psychologist (who’s totally clueless about everything), but even Kate, whom it’s impossible to sympathize with overmuch even though Farmiga plays her with typical intensity. (Kate engages in impromptu sex with John, for example, where her kids could easily stumble on them.) Much of the picture is also based on the explicit terrorization of children, which is not only a thoroughly unsavory way of generating shrieks but is handled in a particularly unsavory fashion here. Various plot turns are also very reminiscent of its genre predecessors—a fire in which somebody’s trapped (see Leroy in “The Bad Seed”), a sequence in which somebody’s trapped beneath the ice of a frozen pond (see “The Good Son”). Homage, anyone?

And the shock techniques employed by director Jaume Collet-Serra aren’t merely cheesy, they’re applied in ways that, even by horror conventions, are totally bogus. Early on we have the “medicine cabinet mirror closing to reveal an unexpected figure” cliché, but it’s a cheat, despite the abrupt music cue. Then there are the instances when we have POV camera pans toward persons with their backs turned, who suddenly turn around to reveal—nothing! And of course the final confrontation is one of those prolonged episodes in which the villain repeatedly comes back from the dead for one or two more assaults. It’s like “Carrie” on steroids, but without an ounce of De Palma’s style; and it’s not only gross but makes the movie, at a full two hours, grossly overlong.

This is yet another offering from Joel Silver’s low-rent Dark Castle outfit, and as usual it boasts grim, gray visuals, this time courtesy of Jeff Cutter, and a score that’s unworthy of composer John Ottman, whose work with Bryan Singer has shown him capable of far better.

For some reason Warner Bros. has chosen to release “Orphan” a bit early in the year. I don’t mean that October 31 would have been appropriate. I’m referring to August, which is the month usually reserved for mangy dogs like this.