Steve Wynn Joe Francis Is 'a Miserable Vicious Assassin'

9/7/2012 2:15 PM PDT

Steve Wynn: Joe Francis Is 'a Miserable Vicious Assassin'

This is awesome ... 70-year-old billionaire casino mogul Steve Wynn just unloaded on "Girls Gone Wild" honcho Joe Francis outside an L.A. courthouse -- calling Joe "a miserable vicious assassin" and a "liar."

Wynn was outside court today for his ongoing defamation suit against Francis -- in which Francis accused Wynn of threatening to kill him and bury him in the desert -- and the casino magnate went OFF.

Wynn called Francis' accusations "the ravings of a miserable vicious assassin, a liar who just didn't want to pay his debt and decided to make up a story about a guy who he never set his eyes on or ever met. Me."

Wynn -- who's seeking $12 mil -- also said he plans to donate whatever damages he's awarded in this lawsuit to charity -- specifically to battered women and wounded soldiers ... minus the lawyers' cut of course.