Where does “mätänäppylä” come from?

mätänäppylä (Finnish) comes from Finnish näppylä, from Finnish la, from Finnish lauantai, from Old Norse laugardagr, from Old Norse laug, from Proto-Germanic laugō, from Proto-Indo-European lewh₃- — to wash.

Ancestry of “mätänäppylä”, step by step

mätänäppylä traces back through two separate lines of ancestry.

via Finnish näppylä

StepLanguageWordMeaning
1Finnishnäppyläpimple
2FinnishlaAbbreviation of lauantai
3FinnishlauantaiSaturday
4Old NorselaugardagrSaturday
5Old Norselaugbath; hot spring; first-person singular past...
6Proto-Germaniclaugōbath, wash; soap, lye
7Proto-Indo-Europeanlewh₃-to wash

via Finnish mätä

StepLanguageWordMeaning
1Finnishmätärotten; fishy; pus
2Proto-Finnicmätäpus; rotten
Every word from Proto-Indo-European lewh₃- →Every word from Proto-Germanic laugō →Every word from Old Norse laug →