White said McGregor would "kick (Mayweather's) ass" in a street fight.
"Floyd better hope he doesn't run into Conor on the street," White told TMZ. "Not only will Conor kick his ass, he'll kick the s--t out of every one of his security guards too."
White's comments came in response to Mayweather, who recently said that he would "slap the s--t" out of McGregor if he ever saw him.
White, in his video, said Mayweather has soft hands.
"His hands are like peanut brittle," White said. "He has to wrap them a million times so he doesn't break them."
White said Mayweather wouldn't dare try to slap the UFC lightweight champion, and if he did, McGregor would "kick his head to another planet" and then "murder every one of his security guards."
White said a boxing match between the two fighters would never happen, but it's more likely to occur than Mayweather ever trying to slap McGregor.
"I promise you Floyd, I promise you. You will never try to walk up and slap Conor McGregor."