Nevertheless, this nouveau moonlighting continues to be exalted ­as cool, empowering or freeing. This mantra is false: Side hustles are not simply a new version of working as a “wage slave” so that we can do what we love in our off hours. Instead, far more often, people take on second or third side hustles because of wage stagnation or low pay at their full-time jobs.

Over the past few years, I have interviewed dozens of people who work a full-time job or close to it — teachers, professors, administrators and nurses, among others — and supplement their incomes by driving for Lyft or serving as a barista. They are not doing it for the glamour. They need these second jobs because their first jobs don’t cover astronomically rising rents, record health care costs or swelling college tuition. A full 30 percent of Americans do something else for pay in addition to their full-time jobs, according to an NPR/Marist survey last year.

Yet this sales pitch for the “side hustle” takes what we once called, more drably, another job and gives it a gloss, with a tiny shot of Superfly, disguising unstable working hours and a lack of bargaining power as liberation. You can see the twisted alchemy of what Reddit’s founder Alexis Ohanian has called “hustle porn.”

Commercial websites like Side Hustle Nation extol the joy of the new unstable labor, although its payoff actually arrives for only a few. As Nick Loper, the site’s “chief side hustler” writes, “My escape route was a side hustle business I built in my spare time — and you can do it too.” Medium has a whole Side Hustle publication. It bears the legend “You’re more than your day job.”

This language tries to make the dreary carousel of contemporary life sound more fun. “The phrase the ‘side hustle’ has gained a strange kind of prestige from downwardly mobile, college-educated tech workers,” said John Patrick Leary, the author of “Keywords: The New Language of Capitalism,” a sharp recent book on this troubling new lingo. Its glitz and energy derives from “a hip-hop genealogy,” although the side hustles name-checked in that genre are perhaps not the same as those imagined by Uber.