Early in Nick Cassavetes’ chick-flick misfire, Cameron Diaz says, “I’m too old for this s**t.” Indeed she is. Not that the star isn’t still gorgeous. But the last time there was a movie about a bunch of females who bound together to take vengeance on an unfaithful cad who was two-timing them all—“John Tucker Must Die”—the conspirators were high-school coeds, and it seemed nutty even for girls of that age to get into such a tizzy over any guy, although he was the campus stud and sports star. In “The Other Woman” two of the trio are in their early forties, and the notion that at that age they’re still basically defining themselves in terms of their relationship to a man is demeaning to women generally, particularly since the movie is obviously aimed at them—and written by a woman to boot. (The man, it should be added, doesn’t seem like such a great catch in any event.)

But this is a film that’s insulting to women not only in those terms, but because it’s exploitative of them physically. It takes pains to show Diaz and another of the stars, Kate Upton, running around in bikinis as often as possible, leaving little to the imagination. One wonders how wives who bring their husbands (or girls their boyfriends) to the movie will react when their partners start drooling over these sequences.

Even apart from such considerations, “The Other Woman” is pretty awful. It begins with Carly Whitten (Diaz)—supposedly a powerful NYC attorney, though as far as we can see her only real distinction is an awesome wardrobe (at the beginning she’s handed a major merger to oversee, but that plot thread is completely dropped when the plot kicks in)—being involved with hunky hedge fund manager Mark King (Nikolas Coster-Waldau). When he’s called away to deal with a plumbing problem at his Connecticut house—missing an introduction her father (Don Johnson) in the process—she takes her dad’s advice to surprise him at his place in sexy garb. Unfortunately, when she arrives the door is answered by Mark’s mousy wife Kate (Leslie Mann).

This is the same preliminary set-up you might recall from last year’s “Baggage Claim”—or perhaps not, since it was little seen—but the script goes off in a different, though no less terrible, direction when gonzo Kate shows up at Carly’s office, making an embarrassing scene there before showing up at her apartment to ask for help against the man who’s wronged them both. The two decide to spy on Mark, only to discover there’s a third woman in his life—curvaceous young Amber (Upton), who as far as this viewer can discern has no job at all. When she finds out Mark’s been lying to her too, she joins forces with the older duo to punish him.

It would be dispiriting to go to undue lengths recounting what the women do; their schemes involve stuff like putting hair remover in Mark’s shampoo, adding laxatives and estrogen to his drinks and finally removing all the illegally-gotten funds he’s stored in off-shore accounts and informing his business partners of his malfeasance. It all ends in a gruesome final confrontation in which the guy winds up bloodied and financially ruined—a finale that, with its unpleasant level of violence, comes across as tonally off the charts.

But that’s just the culminating misstep in a movie that has plenty of them. Some ugly potty humor seems designed to exceed the notorious bit in “Dumb and Dumber,” and earlier on there’s a vomit scene that’s almost equally depressing. Slapstick moments, like one in which Diaz supposedly crashes onto a lawn from a second-storey window, literally fall flat. And the script is peppered with clichés of the genre that grate. A big, slobbering dog? Check. (And watch it urinate on a hardwood floor, too.) A wise-cracking secretary? Check. (And fill your need for diversity by having her played by Nicki Minaj.) A good new guy for Carly? Check—he’s Kate’s handsome, supportive brother Phil (Taylor Kinney), who couldn’t be sweeter. And needless to say, Johnson’s father figure is a charming philanderer working toward a sixth marriage. No prizes for guessing whom he’ll wind up with.

The performances jibe with the shabbiness of the material. Diaz is broad and curiously brusque, while Upton is pretty but dull. Minaj, Johnson and Kinney do what the script demands and nothing more, while Coster-Waldau exudes sleaze and endures humiliation several times over. Then there’s Mann, whose over-the-top mixture of primness and goofiness is irritating at first appearance, only to grow more and more annoying as the plot rolls on. The fact that we’re asked to accept the fact that Kate’s also a brilliant “idea person” takes implausibility to new heights. On the technical level “The Other Woman” is okay, though cinematographer Robert Fraisse gives the images a plastic gloss that marks sitcom style.

Numbingly stupid and uncommonly nasty, this is the sort of chick flick that gives chick flicks a really bad name.