Unpredictable, erratic or fickle; mercurial.
The metal mercury.
An amalgam of mercury and tin applied to the backs of mirrors, quicksilvering.
To overlay with quicksilver.
To treat with quicksilver.
Negligent or imperfect.
Not keeping good faith; disloyal; not faithful.
Not honest or upright.
Not faithfully rendering the meaning of the source language; incorrect.
Not having religious faith.
Adulterous.