Plutonian

The adjective is derived from Latin Plūtōnius (“of or relating to Pluto, Greek and Roman god of the underworld”) +‎ -an (suffix forming adjectives). Plūtōnius is from Ancient Greek Πλουτώνιος (Ploutṓnios, “of or relating to Pluto”), from Πλούτων (Ploútōn, “Pluto”) (from πλοῦτος (ploûtos, “riches, wealth”) (ultimately from Proto-Indo-European *plew- (“to fly; to flow; to run”)) + -ων (-ōn)) + -ιος (-ios, suffix forming adjectives). The English word is cognate with Middle French plutonien (modern French plutonien). The noun is derived from the adjective.