östdansk

Compound of öst (“east”) +‎ dansk (“dane”).

For the humorous sense:

• Partly because the Swedish region Scania lies directly east of the Danish capital Copenhagen.
• Partly because it is a popular joke to say that the region is not part of Sweden, but instead a part of Denmark.

östdansk c

1. An east Dane, an east Danish; something originating of eastern Denmark (a person, an object, a phenomenon, etc...).
2. (humorous) synonym of skåning (“Scanian”)

   Synonym: reservdansk

   • 2020 September 12, Rolf Gustavsson, “Min ungdoms bild av Ruhrområdet är passé [My youth's image of the Ruhr area is passé]”, in Svenska Dagbladet:

     I de tidiga tonåren gjorde jag min första riktiga utlandsresa. Familjens årliga dagsutflykt till Tivoli och Zoo räknas inte. Köpenhamn var ju inget utland för oss gamla östdanskar.

     In my early teens, I made my first real trip abroad. The family's annual day trip to Tivoli and Zoo does not count. Copenhagen was not a foreign country for us old Eastern Danes.

• östdanskt (“east-Danish”, adjective)