n.
a. [ L. mercurialis, fr. Mercurius Mercury: cf. F. mercuriel. ]
A mercurial man
Who fluttered over all things like a fan. Byron. [ 1913 Webster ]
The mercurial wand of commerce. J. Q. Adams. [ 1913 Webster ]
n. [ Mercurial + -ism. ] (Med.) The syndrome produced by poisoning due to exposure to mercury, it fumes, or its compounds;
n.
v. t.
v. i. To be sprightly, fantastic, or capricious. [ Obs. ] [ 1913 Webster ]
adv. In a mercurial manner. [ 1913 Webster ]