Where does “нечистый” come from?
нечистый (Russian) comes from Russian чи́стый, from Old East Slavic чистъ, from Proto-Slavic čistъ, from Proto-Balto-Slavic skīstas, from Proto-Indo-European skidtos, from Proto-Indo-European (s)keyd-.
Ancestry of “нечистый”, step by step
Words derived from “нечистый”