The story
- Proto-Finnic*hak'at'ak
- Finnishhakata
- Proto-Uralic*päŋe
- Proto-Finnic*pää
- Finnishpää
- Finnishpäälle
- Finnishhakkaa päälleder.?
- Swedishhakkapelit
- Finnishhakkapeliitta
- English todayHakkapeliitta
Borrowed from Finnish hakkapeliitta, probably from the Finnish war cry hakkaa päälle (literally “hack on; hit on”).
Etymology from Wiktionary, CC BY-SA 4.0.