Mercurian

Part of speech: adjective, noun

Definitions

1. Relating to the planet Mercury or possessing qualities associated with the Roman god Mercury, such as eloquence, swiftness, or changeability
2. Pertaining to the celestial body Mercury or embodying characteristics linked to the deity Mercury, including agility, communication skills, and variability
3. Associated with either the planet Mercury or the mythological figure Mercury, often signifying traits like quickness, expressiveness, and adaptability

Etymology: Mercurian is about as plain as English derivation gets: it is simply the planet's name, Mercury, with the suffix "-ian" attached. That suffix is itself an old inheritance, reaching English through Latin "-ānus" and "-iānus", which formed adjectives meaning "belonging to" or "relating to" a name. So a Mercurian thing is one that relates to Mercury, the planet, or, more loosely, to the Roman god Mercury, whose traits of speed, cunning and messaging the word also picks up. The Latin base "Mercurius" is the name of the god, and the planet took its name from him in classical astronomy, a link the Latin and English forms preserve. The word's use in English is therefore two-directional: it can describe the cold, fast-orbiting planet, or the quicksilver temperament the god was credited with.