1. Liable to sudden unpredictable change
   "mercurial twists of temperament"
   - erratic, fickle, quicksilver 
2. Relating to or containing or caused by mercury
   "mercurial preparations"; "mercurial sore mouth"

1. Relating to or under the (astrological) influence of the planet Mercury
   "the Mercurial canals" 
2. Relating to or having characteristics (eloquence, shrewdness, swiftness, thievishness) attributed to the god Mercury
   "more than Mercurial thievishness"

See also: changeable, changeful, mercury

Encyclopedia: Mercurial

• first cause
• First Council of Constantinople
• First Council of Lyons
• First Council of Nicaea
• first cousin
• first cranial nerve
• First Crusade
• first degree
• first derivative
• First Duke of Marlborough
• First Duke of Wellington
• First Earl Kitchener of Khartoum
• First Earl of Beaconsfield
• First Earl of Chatham
• First Earl of Orford
• First Earl Wavell
• First Epistle of John
• First Epistle of Paul the Apostle to the Corinthians
• First Epistle of Paul the Apostle to the Thessalonians
• First Epistle of Paul the Apostle to Timothy
• First Epistle of Peter
• First Epistle to the Corinthians
• First Epistle to the Thessalonians
• First Epistle to Timothy
• first estate