Cordell Broadus -- Screw Football ... I'm Designing Men's Underwear

Cordell Broadus is trading football jerseys for underwear, but Snoop Dogg's son isn't just wearing the fancy drawers ... he's designing them.

Cordell shocked UCLA (and his dad) when he quit the football program to focus on his film production company -- but TMZ Sports has learned he has another side hustle with underwear co. PSD.

Founder Curt Flaitz tells us teaming up with Cordell was a no-brainer ... "He's a creative guy who's young and hungry. And he's been wearing our stuff forever." Cordell and the PSD team met this week to start mocking up designs that target younger buyers. Or as Flaitz put it ... "You know how there's a cool kids table at lunch. We make our products for those people."

Kyrie Irving, Chandler Parsons, and Marshawn Lynch officially rock PSD as celeb endorsers. Snoop's also a big fan of the brand.

Cordell's Christmas shopping just got a little easier.