Pregnant Cardi B Fires Back Over Skin-Bleaching Accusation, 'Y'all Dumb'

Cardi B is not having it ... delivering the clapback of all clapbacks when someone had the nerve to ask online if she’d been bleaching her skin.

The rapper quoted the offending X post Wednesday ... calling out the skin-bleaching accuser as dumb, and explaining her paler look is due to her unborn baby sucking the life out of her -- leaving her pale, anemic, with sunken eyes and popping veins.

Cardi threw in that sunbathing was also a no-go ... 'cause she gets hot and dizzy in no time, making it a real health hazard ... so for the time being, she has to embrace her natural, paler complexion.

She finished off with a classic Cardi mic drop ... telling folks to "stop thinking with your a**hole."

The skin-bleaching drama started after Cardi posted an X pic of her pal rubbing her pregnant belly ... where it simply looks like the camera flash caught her at an odd angle, making her look lighter than usual.

And this ain't Cardi's first rodeo ... she's pregnant with baby No. 3, so clearly she's got it totally under control when it comes to keeping her pregnancy safe and sound.