Where does “dzieciobójczyni” come from?

dzieciobójczyni (Polish) comes from Polish dzieciobójca, from Polish -ca, from Old Polish -ca, from Proto-Slavic -ьca, from Proto-Slavic -ьka, from Proto-Balto-Slavic -ikaʔ, from Proto-Indo-European -ikeh₂.

Ancestry of “dzieciobójczyni”, step by step

Step	Language	Word	Meaning
1	Polish	dzieciobójca	infanticide
2	Polish	-ca	Forms agent nouns
3	Old Polish	-ca	forms agent nouns
4	Proto-Slavic	-ьca	Denominal, forms diminutives; Deverbal , forms...
5	Proto-Slavic	-ьka	—
6	Proto-Balto-Slavic	-ikaʔ	—
7	Proto-Indo-European	-ikeh₂	—

Every word from Proto-Indo-European -ikeh₂ →Every word from Polish -ca →Every word from Proto-Slavic -ьka →