eigenspaceWit, unker, Git: The lost medieval pronouns of English intimacy
https://www.bbc.com/future/article/20260408-the-extinct-english-words-for-just-the-two-of-us
Boy that unc/uncer looks tantalisingly close to modern German uns/unser. Wiktionary seems to have it descending from a different PIE root, n̥s vs n̥h -- I'm not at all familiar with PIE though.
That was my first thought too! So many things in old-english are very very close to modern German, so it's sometimes surprising to see these false-friends.
Oh, you mean “Falsche Freunde”?
I have no idea how to say that idiomatically in German, but it struck me that those are both “true” friends.