Quick to change one’s opinion or allegiance; insincere; not loyal or reliable.
Changeable.
To puzzle, perplex, nonplus.
To deceive, flatter.
Unpredictable, erratic or fickle; mercurial.
To overlay with quicksilver.
To treat with quicksilver.
The metal mercury.
An amalgam of mercury and tin applied to the backs of mirrors, quicksilvering.