When you smoke so much weed that you permanently seem high when sober, permanent stoner eyes (closed ish eyes) and permanent stoned behaviour, people may ask you if you're stoned when you're sober if you're permafried
Charles: whats up with Greg's eyes?
Neil: oh he's permafried thats why, hes actually soberrn
To have taken so many drugs your brain is irreversably fried
John Saunders went way too hard for way too long but hasnt touched drugs in 10 years. Even after such a long period of sobriety he shows signs of serious brain damage and as such is permafried