Conor McGregor just UNLOADED on the WWE -- saying most of the pro wrestlers are "p**sies" -- and blasted Brock Lesnar as a juiced up cheater.
McGregor was on a conference call to promote UFC 202 when he was asked if he'd ever consider doing a stint in the WWE ... and that's when he went off.
"I haven't really thought about it," McGregor said ... "For the most part, those WWE guys are p**sies."
"They're messed up p**sies if you ask me."
McGregor said there are some people he respects over there -- including the McMahons, Triple H and The Rock.
But when asked about Brock Lesnar ... he fired even more shots.
"I mean fair play to Brock, he got in and fought [at UFC 200] ... but at the end of the day he's juiced up to the eyeballs ... so how can I respect that?"