LenDale White just went scorched earth on Philip Rivers over his comments that the Chargers ain't stressing about Melvin Gordon's holdout ... straight-up calling the QB a "p***y."

MG is holding out of L.A. camp this month because he wants a new contract ... and when Rivers was asked about it this week -- he seemed to brush it off.

"We love Melvin," Rivers said, "but we’re going to go with what we’ve got. It’s a pretty dang good group.”

That didn't sit well with White, who attacked Rivers for the comments ... saying, "Exactly why u better do what best for you smh phill a p***y for that !!"

Rivers' words also struck a chord with Chiefs star safety Tyrann Mathieu, who wrote on social media, "DAMN."

Even Gordon himself weighed in ... responding to Mathieu's tweet with, "Wild right !!"

It's not a great look for the Chargers and Gordon ... things have reportedly gotten VERY contentious as the star RB wants a deal similar to the $57 MILLION one Todd Gurley inked last year.

In fact, reports say contract talks have stalled so much ... Gordon could be a trade candidate sometime this summer.

For his part, Gordon has remained quiet on his contract demands ... but players all over the league -- including Jets star Le'Veon Bell -- have supported his holdout.