Shaquille O'Neal's Alleged Mistress DESTROYED By Judge -- You're a Dirty Liar

HUGE legal victory for Shaq -- the lawsuit filed by an alleged ex-mistress who claimed the NBA star harassed her following their breakup has been dismissed ... because the judge says she's a dirty LIAR.

As we reported, Vanessa Lopez filed her lawsuit against Shaq back in 2010 claiming she was his mistress for 5 years ... and once she broke up with him, he launched a campaign to harass her and make her fear for her safety.

But the Florida judge just lowered the legal boom on Lopez in his ruling -- claiming the court CAUGHT HER in several lies ... proving it's impossible to believe anything that comes out of her mouth.

"[Lopez] lied often. She lied about facts important to the defense, and she demonstrated an utter disrespect for the system of justice," the judge stated.

Among Lopez's lies -- the judge says Vanessa claimed she "did not know of" any previous restraining orders that had been issued against her ... when there were official records showing she was hit with one stemming from a case involving an ex-boyfriend.

The judge says there's also proof she lied about her legal history with NBA star Kenyon Martin ... who had accused her of stealing his credit card and running up charges.

And there's this ... Vanessa's lawyers completely deserted her almost immediately following her deposition earlier this year ... a huge red flag.