mercurial Meaning, Definition & Usage

  1. adjective satellite liable to sudden unpredictable change
    fickle; erratic; quicksilver.
    • erratic behavior
    • fickle weather
    • mercurial twists of temperament
    • a quicksilver character, cool and willful at one moment, utterly fragile the next
  2. adjective relating to or under the (astrological) influence of the planet Mercury
    • the Mercurial canals
  3. adjective relating to or having characteristics (eloquence, shrewdness, swiftness, thievishness) attributed to the god Mercury
    • more than Mercurial thievishness
  4. adjective relating to or containing or caused by mercury
    • mercurial preparations
    • mercurial sore mouth

WordNet

Mer*cu"ri*al adjective
Etymology
L. mercurialis, fr. Mercurius Mercury: cf. F. mercuriel.
Definitions
  1. Having the qualities fabled to belong to the god Mercury; swift; active; sprightly; fickle; volatile; changeable; as, a mercurial youth; a mercurial temperament.
    A mercurial man Who fluttered over all things like a fan. Byron.
  2. Having the form or image of Mercury; -- applied to ancient guideposts. Obs. Chillingworth.
  3. Of or pertaining to Mercury as the god of trade; hence, money-making; crafty.
    The mercurial wand of commerce. J. Q. Adams.
  4. Of or pertaining to, or containing, mercury; as, mercurial preparations, barometer. See Mercury, 2.
  5. (Med.) Caused by the use of mercury; as, mercurial sore mouth.
Mer*cu"ri*al noun
Definitions
  1. A person having mercurial qualities. Bacon.
  2. (Med.) A preparation containing mercury.

Webster 1913