I learnt today that the Swedish word blunda means to shut one’s eyes, to keep one’s eyes shut, to refuse to see something; to pretend not to know about, or to ignore. It comes from the Old Norse word blunda (to shut the eyes, to doze) [source].
Related words include blund (good sleep, wink), blund for (to wink at, turn a blind eye to), and Jon/John Blund, a character from folklore who brings good sleep and dreams to children, known as the sandman in English.
In Icelandic blunda means to doze.
Wink is also linked to sleep in English – you might take forty winks, or not sleep a wink, which might make you blunder about.
The English word blunder comes from the same root, via the Middle English blunder, blonder (disturbance, strife), and blonden, blanden (to mix; mix up); and blunden (to stagger; stumble), from the Old Norse blunda [source].
Blunder is also a Swedish word meaning blooper, gaffe, trip, bloomer and blunder.