mercurial

& s. [Lat. mercurial is, from mercurial; Ital. mercuriale.] mercurius = mercury (q. v.); Fr. mercuriel; Sp. A. As adjective : 1. Of or pertaining to Mercury; having the qualities ascribed to Mercury. An astrological word introduced when men believed that those who were born while the planet Mercury was in the ascendant would nece arily be light-hearted; sprightly, gay, flighty, changeable, fickle. "Piggott being a more forward and mercurial man got. glory of it among most scholars."-Wood: Fasti Oxon., vol. ii. *2. Pertaining to Mercury, regarded as the god of trade; hence, pertaining to trade or money-making. "Thus tickling, lying evasion, with several other such like cardinal virtues, are a sort of properties pertaining fe ion."-P. Whitehead: Gymnasiad , bk. i. (Note.) to the practice of the law, as well as to the mercurial pro taining or consisting of quicksilver. 3. Of or pertaining to mercury or quicksilver; con 4. Caused by quicksilver; as, a mercurial disease. B. As substantive: 1. A person of a mercurial temperament; one who is sprightly, changeable, or fickle. 2. A preparation of mercury, used as a drug.