Adrien Broner just learned the hard way ... if you're going to record a threesome on your phone -- DON'T LET IT GO PUBLIC!!!
A Nevada court just ordered the boxer to fork over $175,000 (plus other fees) to one of his co-stars from a 2013 romp after the footage mysteriously surfaced on World Star Hip Hop.
Broner had argued that he didn't intentionally leak the video (which was shot with the consent of his 2 partners) ... but he had lost the phone he shot it on and someone else posted it.
So, why didn't Broner have a password on his phone?
The boxer testified that he has 3 phones on him at all times -- a business phone, a family phone and a "ho phone" (his actual words).
Broner says he simply never bothered to password protect the ho phone -- so anyone could've had access to his x-rated library.
The jury bought Broner's story and found that he did not act intentionally ... just negligently ... and ordered him to fork over the $40k in lost wages and $135k for pain and suffering.
The plaintiff's attorney, Kevin Hansen, tells TMZ Sports, "I'm happy to see that the jury saw through the defendant’s games. They saw [my client] for who she is and Broner for who he is."