Where does “неумолимый” come from?
неумолимый (Russian) comes from Russian умоли́ть, from Russian моли́ть, from Old East Slavic молити, from Proto-Slavic modlìti, from Proto-Balto-Slavic *maldī́ˀtei, from Proto-Indo-European meldʰ- — to ask, pray, speak; lightning.
Ancestry of “неумолимый”, step by step