Dana White Tells Floyd Mayweather He's Dumb to Turn Down McGregor Fight (VIDEO)

Dana White could not be clearer ... Floyd Mayweather has stupid written on his forehead for dismissing his $25 million offer to fight Conor McGregor.

Dana thinks Floyd should be grateful to him for offering him enough to pay Uncle Sam and Pristine Jewelers.

What's more ... the UFC honcho thinks its ridiculous that Floyd is under the delusion he's worth more than Conor.

We got Floyd out earlier Friday, and he scoffed at Dana's offer.