fuscous (en)

(adjective) of any of several colors averaging a brownish gray / dark and somber in color (literary term)

lissome (en)

(adjective) easily flexed / (adjective) lithe / (adjective) nimble

polysemous (en)

when a word or phrase has multiple meanings (from Greek)

stygian (en)

(adjective) extremely dark, gloomy, or forbidding; refers to the River Styx of the underworld Hades in Greek mythology;