Rock critics, on a quest for ever greater snobbery, are seldom satisfied describing bands as “rock ’n’ roll” anymore. The splintered genre has bred so many incestuous subgenres that its family tree is more like a million-knotted Venn diagram. Journalists are left to desperately grasp the air at such terms as “sleaze rock,” “cowpunk,” “southern metal,” “speed metal,” “psychobilly” — all designations swimming inadequately around  bands that are perfectly content being referred to as rock ’n’ roll — bands such as Atlanta’s Nashville Pussy, which blew the ceiling off  Billy O’s last week.

When adjectives like raunchy and nasty so immediately come to mind and seem to envelope the entire band like the whiskey vapor it radiates, I suppose it’s natural to want to give it a name reflecting that overpowering aroma. But upon seeing Nashville Pussy on that Wednesday night, it was clear that any of the aforementioned subgenres that could be pinned to the band would obscure the straightforward simplicity of the sounds emanating from its Marshall amplifiers. It was also clear that any generic term loosely tethered to some singular aspect of the performance such as lyrical content (sex, booze and driving fast; or the southern flair — Levi’s and trucker hats) or the risqué women on lead guitar and bass, would distract from the fact that the band hasn’t really invented a new genre at all; it just plays loud rock ’n’ roll so incredibly well, and with such genuine badassery that the real raunchy, nasty personalities of the members shine through the music. How about “badass rock”?

As I wandered the sea of Pabst tall cans, clutched happily by indigenous rockers, the show opened quietly, with local metal band Power of Cronos punctuating the silence of the bar’s first rounds with some thrash- and British heavy metal-influenced scorchers about the usual metal subjects: vikings, decapitation and something called “womping,” which evidently has to do with off-roading.

As the crowd filled out and the irreverent reverends in Ventura comedic bluegrass ensemble Big Jugs took the stage, it was beginning to feel more like an inebriated barn dance, as they stomped and strummed their brand of hillbilly country-folk about fellatio, crack cocaine, lesbians and the preferred number of shots to take (answer: three). Both opening acts, while worlds apart musically, together stood as a surprisingly appropriate prelude to what was to come.

They entered the stage as though they were entering an arena, emerging single file from backstage (Billy O’s kitchen) after a period of private pre-partying with Slayer guitarist Jeff Hanneman (seriously, he was there) and seizing the stage with almost zero dicking around.

While influences can be inferred immediately — Motorhead, Guns N’ Roses, Ted Nugent, all forms of outlaw country — the result is a unique brand of hard rock mayhem. Wild-haired lead guitarist Ruyter Suys, wearing a Harley Davidson T-shirt cut down the middle and barely held together by safety pins, solos like she’s summoning a demon. Lead singer/guitarist Blaine Cartwright, balding while proudly sporting a halo of long black hair, snarled and sang into the microphone as if in a moonshine induced trance.

Nashville Pussy, a band that gave us an hour and 15 minutes of nonstop rock ’n’ roll, ended the set ceremoniously with Suys spitting a triple of bourbon in the air to shower the crowd.  “Was that Jim Beam?” I asked her afterwards “I don’t fuckin’ . . ..” she replied, and flicked a guitar pick (or perhaps a booger) at me. Well done.