adj. & n.
--adj.
1. (of a person) sprightly, ready-witted, volatile.
2 of or containing mercury.
3 (Mercurial) of the planet Mercury.
--n. a drug containing mercury.
Derivatives:
mercurialism n. mercuriality n. mercurially adv.
Etymology: ME f. OF mercuriel or L mercurialis (as MERCURY)