Silly Chloe Grace Moretz. Did you never see the French drama, “The Piano Teacher?” Scared of movies with subtitles?

If you had, you’d have dashed for the door the MOMENT Isabelle Huppert sat at the keyboard and launched into Liszt’s “Liebestraum.”

“Love Dream” or not, that petite French sixtysomething is not to be trusted in that “teacher” guise, or as “Greta,” the Social Security-eligible, piano-playing stalker in this quiet, chilling thriller from the director of “The Crying Game.”

Its suspense is of the lull-you into complacency variety. The jolts are real-world shocks, a recent college graduate/NYC waitress (Moretz) who realizes the sweet, lonely widow she just returned a lost-purse to has “lost her purse” more than once, has charmed and engendered pity from other young women before her.

And once Greta Hideg has taken a shine to you, she will, as Glenn Close once put it, “not be ignored.”

Rich girl Franky and rich Smith College classmate Erica (Maika Monroe) share a tony loft in Manhattan, where Erika spends Daddy’s money and does a lot of yoga and Franky gets her Manhattan feet wet by waiting tables at a swank restaurant.

Franky is no small town girl. She’s from Boston. So Big Apple-wise Erica’s “This city’s going to eat you alive,” seems a tad unjustified.

But Franky is a trusting soul, insisting on returning the purse she finds on the subway, submitting to the friendly entreaties of its owner, Greta, who lives in a rundown brownstone and apparently has a daughter she misses.

Franky misses her mom. She died less than a year ago.

Shared meals, a visit to the pound to find Greta a shelter dog to ease her loneliness, it’s all a bit much for the roomie, who abruptly accuses Franky of adopting “this woman as your surrogate mom!”

Franky? “Where I’m from, this is what we do” — be nice, polite and compassionate.

It takes no time at all for Franky to figure out the jaded New Yorker was right, that there’s something creepy about Greta, clingy beyond clingy.

And tearing away from the woman she promised she’d stick with, as friends, “like chewing gum,” proves damn near impossible.

Jordan, who made his name on the big screen with 1986’s “Mona Lisa,” and most recently gained notice for TV’s “The Borgias,” isn’t known for thrillers. He does like his twists, though. And violence. And he always gives his actors the close-ups that close the deal on us making our minds up about characters.

Moretz sells Franky’s instant alarm bells and rising discomfort at how Greta can inject herself into her life, regardless of whether she’s wanted there.

Greta knows where she works. She can figure out where she lives and has a good idea of who she lives with. Things are about to get real.

All-knowing Erica has warned Franky and us that “The crazier they are, the harder they cling.” And Greta clings hard. She’s got leverage, too. Franky worries about what she’ll do, and about the dog she just took in. As do we.

The money shot in “Greta” would be when Huppert turns that “like chewing gum” line around on us all — chewing away, coldly letting Franky know that “We need to talk” and no, she’s not going anywhere until they do.

The plot, co-written by Jordan, is conventional to the point of elemental. Jordan introduces the cops into the situation early, teases us with possible easy resolutions to this living nightmare and teases us again when those turn out to be red herrings.

But Huppert makes Greta scarier than she has any right to be. Moretz makes us believe that there are “Mommy Issues” driving her fear of this stranger.

And Monroe, Moretz’s “Fifth Wave” co-star (best-known for “It Follows”), has just enough edge to make Erica a New Yorker newcomers to the city might want to listen to when she barks out a warning, even if it’s hard to take somebody this into yoga — and yoga pants — that seriously.

MPAA Rating: R for some violence and disturbing images

Cast: Chloe Grace Moretz, Isabelle Huppert, Colm Feore, Stephen Rea

Credits:Directed by Neil Jordan, script by Ray Wright and Neil Jordan. A Focus Features release.

Running time: 1:38