"Real Housewives of Miami" star Lisa Hochstein does NOT have sex for money and she's suing some random woman on the Internet who said that she did.

Hochstein recently filed a lawsuit against a woman named Jessica Lederman -- claiming she suffered "severe emotional distress" after Jessica blasted her in the comment section of an entertainment news website.

According to docs, Jessica wrote "Lisa was an escort who also did soft porn in Vegas" ... in response to an article about Lisa joining the "Real Housewives" franchise..

But Hochstein says it's a bold-faced lie and that she's never been in the escort business or done soft core porn in Las Vegas. Hochstein claims Jessica's remark damaged her reputation and threatened both her employment and social life.

Pretty random to go after someone who commented on a web site ... but to each their own.

Hochstein is suing for more than $15,000. A judge has yet to rule.