безразли́чный (Russian) comes from Russian безразличие, from Russian разли́чие, from Bulgarian ра́злика, from Bulgarian -ка, from Proto-Slavic -ьka, from Proto-Balto-Slavic -ikaʔ, from Proto-Indo-European -ikeh₂.
безразли́чный (Russian): indifferent, apathetic, nonchalant