Marty Jannetty is now claiming self-defense in the apparent death of a man he says he killed 47 years ago ... saying he used a brick to fatally fend off a rapist.
The ex-pro wrestling star called in to the Boston Wrestling Sports show on Wednesday night -- where he was questioned about a bizarre Facebook post in which he suggests he killed a guy and dumped the body in the Chattahoochee River sometime around 1973.
At first, 60-year-old Jannetty tries to be careful about the language he uses ... but ultimately describes an incident involving a male bowling alley employee who allegedly tried to "rape" him in a car behind a building in Georgia.