Real-life female baddies are still so uncommon onscreen, though, that they almost seem heroic , not dangerous, by default. “There’s no doubt that people are going to think it’s a female empowerment movie,” Wu said, “because if you look at the highlight reel of the movie, it’s badassery.”

But she added, “We’re not trying to romanticize that life. Whereas in ‘Goodfellas,’ the first line is, ‘I always wanted to be a gangster.’”

The story is told through Wu’s character, who begins working at a club out of economic necessity, only to realize that stripping has its own financial hierarchy. Dancers are often at the bottom; club managers, security and D.J.s can all take a cut. The drug-and-fraud scheme that Lopez’s Ramona concocts — and the leg-up she offers as a friend — is a lifeline, especially in the wake of the recession, when the status the women have precariously reached tumbles down. The movie, said Wu, focuses on “the societal structures they have grown up in and the backgrounds that have given them very few choices of how to survive and flourish in this world.”

Authenticity mattered. Scafaria and her cast made many visits to strip clubs, and had a stripper as an expert and comfort consultant on set. “She would say little things like, ‘The guys say “please” a lot more,’” Scafaria reported. They shot in an actual club, Show Palace in Long Island City, Queens, where, after an open call, they cast several real-life dancers and a manager.

Lopez and Wu committed themselves to the moves, installing stripper poles in their homes to train. Even for Lopez, a lifelong dancer, it was jolting. “I was incredibly nervous,” she said. “I had to be up there, and I had to kind of bare myself — my soul and my physical body — in a way that I hadn’t in any other movie.”