It should be ‘Lappen’ in sense ‘a,’ a rug or a patch. And Swedish ‘läder’ means leather. So an English translation would be The Leather Patch.I read this as German LEDERLAPPEN
Leder = leather
Lappen = a) rag b) a whiny boy or guy
So a LEDERLAPPEN would mean that BATMAN is a leathery whiny guy
We also have leather rags to clean windows called FENSTERLEDER or LEDERLAPPEN