Where does “koperen” come from?

koperen (Dutch) comes from Dutch koper, from Middle Dutch coper, from Latin cūprum, from Latin cȳprium, from Ancient Greek Κύπρος, from Ancient Greek -ῐος, from Proto-Indo-European -yós — Creates adjectives from noun or verb stems.

koperen (Dutch): copper, coppern; brass, brazen; To copper, mount,...