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.
Of questionable or doubtful quality.
Because he is so sketchy, I always think that he is up to something.
Disturbing or unnerving, often in such a way that others may suspect them of intending physical or sexual harm or harassment.
Not thorough or detailed.
Roughly or hastily laid out; intended for later refinement.
Resembling a comedy sketch, of sketch quality.
Suspected of taking part in illicit or dishonorable dealings.