Having the qualities fabled to belong to the god Mercury; swift; active; sprightly; fickle; volatile; changeable; as, a mercurial youth; a mercurial temperament.
- Roman Mythology Of or relating to the god Mercury.
- Astronomy Of or relating to the planet Mercury.
- Having the characteristics of eloquence, shrewdness, swiftness, and thievishness attributed to the god Mercury.
- Containing or caused by the action of the element mercury.
- Quick and changeable in temperament; volatile: a mercurial nature.
- A pharmacological or chemical preparation containing mercury.