mercurial (2009-10-25)

Part of Speech: adjective

Pronunciation: [mêr-'kyUr-ee-êl]

Definition: Having the characteristics of the element mercury (swift, changeable, temperamental); pertaining to the Roman god Mercury or having the characteristics imputed to him (eloquence, shrewdness, swiftness, fickleness—or a relation to commerce).

Usage: Today's word offers a wide array of interpretations, so be careful to use it in a clarifying context, "His lack of mercurial (commercial) aptitude allowed him to slide mercurially (swiftly) into bankruptcy." The swiftness of the winged feet of Hermes/Mercury is most often associated with this word, however, "His marriage to the CEO's daughter sent his career into a mercurial ascent." It can also mean unpredictably changeable in direction as uncontained mercury: "His temperament is a bit too mercurial for a school superintendent."

Suggested Usage: The adverb is "mercurially," the noun "mercuriality," and the verb is mercurialize "treat with mercury, cause to be mercurial." Other forms have been used but have not widely survived, e.g. the adjective "mercurious" and the verb "mercuriate."

Etymology: While the Roman god Mercury (Mercurius) was originally associated with trade, he eventually was equated with the Greek god Hermes, he of the winged feet. The speed imputed by winged feet recommended his name to the liquid metallic element used in thermometers and batteries, otherwise known as "quick silver." However, we still find the root of Mercury's name in "commerce" and "merchant," all from Latin mercari "to trade," a verb from the noun merx, merc- "merchandise."