Where does “nurinpäin” come from?

nurinpäin (Finnish) comes from Finnish päin, from Finnish pää, from Proto-Finnic pää, from Proto-Uralic päŋe — head.

Ancestry of “nurinpäin”, step by step

nurinpäin traces back through two separate lines of ancestry.

via Finnish päin

StepLanguageWordMeaning
1Finnishpäinagainst, to, on etc; Used to indicate approximate...
2Finnishpäähead; end, tip
3Proto-Finnicpäähead
4Proto-Uralicpäŋehead

via Finnish nurin

StepLanguageWordMeaning
1Finnishnurinover, inside out, upside down wrong way round or not standing up
2Finnishnurjawrong; adverse
3Proto-Finnicnurjawrong, bad, poor
Every word from Proto-Uralic päŋe →Every word from Proto-Finnic pää →Every word from Finnish pää →