Where does “kääpiörasvahiiri” come from?

kääpiörasvahiiri (Finnish) comes from Finnish kääpiö, from Finnish -io, from Finnish -o, from Proto-Finnic -o, from Proto-Uralic -w.

Ancestry of “kääpiörasvahiiri”, step by step

kääpiörasvahiiri traces back through two separate lines of ancestry.

via Finnish kääpiö

StepLanguageWordMeaning
1Finnishkääpiömidget, dwarf; dwarf star, dwarf
2Finnish-ioForms nouns from verbs or verbal stems; Forms...
3Finnish-oForms result or action nouns from verbs; Forms...
4Proto-Finnic-oForms action/result nouns from verbs
5Proto-Uralic-w

via Finnish rasvahiiri

StepLanguageWordMeaning
1Finnishrasvahiirifat mouse rodent in genus
2FinnishhiiriA mouse, used rather indiscriminately for a...
3Proto-Finnichiirimouse
4Proto-Uralicšiŋeremouse
Every word from Proto-Uralic -w