mercurial

adjective

1. 1

   relating to or having characteristics (eloquence, shrewdness, swiftness, thievishness) attributed to the god Mercury

   erratic behavior

   fickle weather

   more than Mercurial thievishness

2. 2

   liable to sudden unpredictable change

   erratic behavior

   fickle weather

   more than Mercurial thievishness

3. 3

   relating to or containing or caused by mercury

   mercurial preparations

   mercurial sore mouth

   the Mercurial canals

4. 4

   relating to or under the (astrological) influence of the planet Mercury

   mercurial preparations

   mercurial sore mouth

   the Mercurial canals