Amentistic
A person relating to or suffering from amentia
You know those times when you're trying to help someone out but they're so amentistic that they can't see basic logic and sense. The kind of people that make you want to slit your abdomen so you don't have to breathe the same air as them. The kind of people who make you feel like you've lost brain cells after talking to them.
Amentist
A person of severe congenital mental disability.
Teo is trying to help the guy but he's such a fucking amentist that he can't follow simple instructions.