Future mumbles. So does Lil Wayne. Kodak Black mumbles, too. If you’ve followed popular rap music for the past couple of years, you’ve observed the rise of the term “mumble rap,” which is ostensibly a strain of hip-hop that prizes woozy, marble-mouthed flows over the clarity and urgency of traditional rapping by the likes of Kendrick Lamar. “It’s all about being lit,” Lil Uzi Vert once explained, while not explaining anything.

There are two ways to think about “mumble rap.” First, as a loose contemporary hip-hop subgenre that apparently includes rappers such as Lil Uzi Vert and 21 Savage as well as the other, aforementioned examples. I say “apparently” because — outside of being young, and being black, and being rappers — Lil Uzi Vert and 21 Savage don’t have much in common. They’re two very different personas who make very different rap music.

Which brings us to the other way to think about “mumble rap” — as a reclaimed pejorative that fails as a musical description, and that gets trickier to define the more rappers it encompasses.

The sentiment has been kicking around since last April, thanks largely to Desiigner’s no. 1 single, “Panda” — a song so wildly unintelligible that the rapper spent 90 percent of his video interviews last year repeating the lyrics slowly so that fans could understand what he’s even saying on it. Two months later, Wiz Khalifa used the term “mumble rap” on Hot 97 to describe “lil homies” who “don’t want to rap” as hip-hop’s dominant fad, prompted by an Ebro question regarding Lil Yachty and Lil Uzi Vert.

But it was Pete Rock who truly popularized the term in September when he criticized Yachty in a couple of Instagram captions, following the upstart’s comments on the Notorious B.I.G. being “overrated” and disparaging of ’90s rappers and their fans as “old and washed up.” Once Yachty shot back at Pete Rock, fans and critics rallied around “mumble rap” as hip-hop’s great generational fissure — even as Yachty himself has pointed out that he doesn’t really mumble on songs. “I’m not saying I really be spitting,” he recently told The Breakfast Club, “but I feel like I open up my mouth, or I be harmonizing and singing. I’m not tripping. As long as I continue to prosper, I’ll take mumbling to the top.”

Granted, most popular subgenre terms become reductive after a point. “Trap,” which theoretically describes hard Atlanta street rap, has somehow come to include all bass-heavy synth beats with stuttering hi-hats, regardless of where they come from or what kind of rapping goes over those beats. But “mumble rap” is more ill-fated than “trap,” “gangsta,” “backpack,” or “boom bap” — or even “mumblecore,” which is now an accepted genre of film — given that the term is, by design, more a messy put-down than a coherent musical (or aesthetic) assessment. If anything, the term is helpful at least as confirmation that young rappers, like them or not, are making new sounds and rendering themselves purely unintelligible to closed minds, as hip-hop has always done.

All that said, Yachty doesn’t mumble. He babbles excitedly like a parent talking to a happy infant, but mumbling — commonly defined as speaking at an imperceptibly weak volume — isn’t really his style. Young Thug mumbles sometimes, but he mostly yelps and wails. That’s his vocal talent. Not mumbling. And the fact that two of the poster children for “mumble rap” don’t actually mumble on songs is the red flag that the term isn’t a useful subcategorization, but rather a point of gratuitous intergenerational conflict about musical taste. Such is the true nature of “mumble rap,” a term that has never been about actual mumbling so much as it’s really about discomfort with how a generation of young musicians has chosen to use their voices in strange, unprecedented ways, and against the wishes of their parents and forefathers.

Unless, of course, you’re talking about Desiigner. He’s definitely mumbling.