"F**k LaVar Ball" -- Joel Embiid.
That's exactly what the Philly 76ers star proclaimed on Instagram Live Tuesday ... just a few days after the Big Baller said Sixers players should stay off Twitter and get in the gym.
ICYMI -- Embiid and fellow Process Truster Ben Simmons tweeted their opinions of BBB during the NBA Draft ... with Embiid asking Simmons to dunk on LaVar's son, Lonzo.
LaVar wasn't havin' it ... telling 97.5 The Fanatic, "when you don’t win and don’t even make the playoffs, and don’t even stay on the court long enough, that’s the best thing you can do is tweet, make some stuff."
"These guys ain’t played a game, always hurt, and at the bottom of the totem pole," Ball added at the time.
"So guess what, get your asses off the goddamn Tweeter, and get in the gym."
So when someone asked Embiid what he thought about LaVar's comments during the IG stream, he unleashed a simple, yet effective 3-word response.