Available Definitions:
1) a. - Having the qualities fabled to belong to the god Mercury; swift; active; sprightly; fickle; volatile; changeable; as, a mercurial youth; a mercurial temperament.
2) a. - Having the form or image of Mercury; -- applied to ancient guideposts.
3) a. - Of or pertaining to Mercury as the god of trade; hence, money-making; crafty.
4) a. - Of or pertaining to, or containing, mercury; as, mercurial preparations, barometer. See Mercury , 2.
5) a. - Caused by the use of mercury; as, mercurial sore mouth.
6) n. - A person having mercurial qualities.
7) n. - A preparation containing mercury.