vaimo.

From Proto-Finnic *vaimo (“spirit, soul”) (compare Estonian vaim (“spirit”)), possibly derived from Proto-Uralic *wajŋe (“(living) spirit”) (compare Northern Sami vuoigŋa (“breath, spirit”), Moksha вайме (vajme), Erzya ойме (ojme, “spirit, soul”), Nganasan бачуˮ (bačuʔ, “soul”)). The original sense of this word in Finnic and Uralic was “spirit (the living soul of a person, which leaves a person when they die)”, but this sense is not found at all in Finnish. The semantic development to “wife” is also shared by Karelian vaimo (although this may be Finnish influence). The semantic shift has not been conclusively explained, although a somewhat similar shift was observable in Estonian, where vaim was used historically to refer to a peasant woman who worked as a day laborer (corvee) at a manor. vaimo was the most common word for the sense “(adult) woman” in Old Literary Finnish, but was later replaced by nainen in this sense.