4:21 PM PT -- A rep for Mayweather tells us he didn't take the photo because he was in a rush to leave the game. As for the teenage fan's claim that Floyd is homophobic ... the undefeated boxer says that couldn't be further from the truth.
Floyd Mayweather REJECTED a male teenage fan's request for a selfie at the Clippers game over the weekend ... and it's all 'cause his nails were painted.
TMZ Sports has learned a young fan was hoping to get a snap with Floyd after the Clippers vs. Grizzlies game at Staples Center on Saturday ... so he hopped on the court to approach him, but was shut down immediately after Mayweather got a glimpse of his nails.
"You got painted nails, I don't take pictures with guys with no painted nails," Floyd is heard saying in the video as his bodyguard gets the fan to back up.
It's not the first time Floyd fans have asked for pics and gotten shut down -- thankfully it didn't turn physical this time. As we previously reported, one of Floyd's guards allegedly beat the crap out of a fan at a Las Vegas mall in November 2019 after a request gone wrong.