If only “Bad Moms” possessed the guts to live down to its title, the wit to deliver on its premise.

An over-reach for a “Hangover” styled spin on motherhood with drugs, sex, booze and “experimentation,” it reaches “raucous” on occasion. There are laughs, a disproportionate number of them coming from the lone trained comic in the cast, Kathryn Hahn.

But like “Ghostbusters,” it loses something every time it wallows in sisterhood sentimentality. Yeah, moms have it rough, and a lot of them screw up a lot of the time. Making sweet and nice about it rubs the edges off the comedy, building up to a finale that is saccharine and sloppy and dissatisfying.

It’s a Mila Kunis vehicle, and therein is problem one. She’s a funny woman, sitcom trained. But she’s bland as Amy, an over-scheduled, hovering/smothering mother of two who does her kids’ homework and agonizes over every bad grade, every soccer team final cut. She’s got no edge.

Amy is the oldest “by far” at the nerdy coffee company start-up where she’s overworked and underpaid. Her compensation, from infantile boss Dale (Clark Duke of “Hot Tub Time Machine”)?

“You guys ARE the greatest generation!”

She’s 32.

Catching dopey husband Mike (David Walton, bleh) in an online sexual relationship with a voyeur is the last straw. But even when she hits the bottle and backs away from her servile life of babying her kids, Amy is too put-together because Kunis doesn’t have the guts to let it all hang out. Morning After Makeup? Perfect. Hangover hair? Just as perfect.

“Checking out” of over-mothering puts Amy in conflict with the dictator of her suburban Chicago middle school, the PTA president, Gwendolyn (Christina Applegate, on the nose). She rules the school from the driver’s seat of her Range Rover, lording over her “Mean Girls” (Jada Pinkett Smith, Annie Mumulo) and judging one and all.

On the plus side, Amy finds two new drinking buddies, home schooler/slave Kiki (Kristen Bell) and free-range barfly mom Carla (Hahn). They close down the pubs, demolish supermarkets and rage about how “impossible it is to be a good mom” in this day and age.

They’ve tried. Well, Carla hasn’t. But the other two have tried to be “Tiger Moms.” They resolve to become Tequila Moms instead.

The laughs, scattered throughout the film and many of them only a mother will appreciate, are strictly of the low-hanging-fruit variety. Amy ends up running against Gwendolyn to free the school from endless PTA meetings, bake sales and high-stress extra-curriculars. To do that, she’s got to appeal to every constituency — “the sad moms, the lesbian moms, the black moms, the black lesbian moms, the drunk moms, the camel-toe moms.”

Hahn, who is EVERYwhere these days, brings a bracing vulgarity to Carla, a broad character broadly played like a broad. She coaches Amy on dating the hunky widower (Jay Hernandez) at school.

“Are you trying to get laid,” she bellows about Amy’s choice of outfit, “or get ADOPTED?”

If every performance was pitched at that level, this might be hackneyed and predictable, but at least it would play.  The laughs just aren’t there. Throwing in a torrent of F-bombs was the male co-directors’ solution to every dead spot.

A moment of nudity, slo-mo montages of the trio getting bombed, their parties, dancing and groping the produce clerk at the supermarket don’t cover the plot holes and laugh gaps.

Still, there are a few more giggles here than in the similarly-themed “Mom’s Night Out,” a faith-based comedy with a lot of the same motherhood gripes and a few good ideas stolen from “Adventures in Babysitting.”

But “Moms’ Night Out” is a no-holds-barred date that ends by 11, a party nobody calls the cops to break up and a “walk of shame” that includes a trip to the spa and hairdressers before coming home after a night spent with a stranger. It’s too prim and proper to be bad.

MPAA Rating:R for sexual material, full frontal nudity, language throughout, and drug and alcohol content

Cast: Mila Kunis, Kristen Bell, Kathryn Hahn, Christina Applegate, Jay Hernandez, Jada Pinkett Smith, Wanda Sykes
Credits: Written and directed by Jon Lucas, Scott Moore. An STX release.

Running time: 1:41