WWE Hall of Famer Jimmy "Superfly" Snuka has pled NOT GUILTY to murdering his girlfriend back in 1983 ... but says his mental health is so bad nowadays, he doesn't know what day it is.
72-year-old Snuka appeared in court in Lehigh County, Pennsylvania -- where he is accused of killing then-girlfriend Nancy Argentino during an altercation in her hotel room before a wrestling match.
Snuka pled not guilty to 3rd degree murder and involuntary manslaughter.
During the hearing, Snuka made some shocking claims -- including saying he never went to school and can't read or write English.
He also told the judge he suffers from early onset dementia and didn't know where he was today or what day it is.
If convicted, Snuka faces up to 40 years behind bars.