Sllih Etinarg

In certain Amish communes, a Sllih (pronounced Sleigh) is a Pennsylvanian Dutch slang term for someone considered "not wise."

Often paired with Etinarg (pronounced Eden Arg), which means "eternal."
When these terms are used together, it often translates to someone making the same mistakes repeatedly without learning.

He didn't check his horses feet before the trip, what a sllih etinarg!