Michael Rapaport LeBron Shut Me Up ... 'Can't Talk Sh*t'

LeBron James got Michael Rapaport to cut the trash talking and shut his mouth ... and even Rapaport says he's pretty damn impressed.

Look, Rap has a lot of crap about Bron over the years -- he famously called him a "motherf*cker" for dissing his kids back in the day.

But now, Rapaport says LeBron is playing on such another level ... he's been rendered speechless.

"I've never seen anybody do what he's done this playoffs," Rapaort says ... "The biggest sh*t-talker, myself. I've got nothing to say. He's been unbelievable."

There is one guy who's still getting the wrath of Rap -- Drake -- who didn't show up to Game 4 of the Cavs vs. Raptors series to watch his team get swept out of the playoffs.

Rao…