Word of the day · 20 July 2026
mercurial
/məˈkjʊəriəl/
adjective
Liable to sudden and unpredictable changes of mood or mind; lively and quick.
In a sentence
- His mercurial temper made planning meetings difficult.
- The market turned mercurial after the surprise announcement.
- Critics loved her mercurial stage energy night to night.
In an image
Origin
From Latin mercurialis (of Mercury); Mercury named the planet, the god and the metal mercury (quicksilver).
History
Astrology linked Mercury to wit, speed and changeable temper. Chemistry added the image of liquid metal that will not stay still. English writers used mercurial for volatile genius and unstable moods. The word still suggests brilliance with a cost in steadiness.
Nearby words
volatile · changeable · capricious
Temperament that shifts as fast as quicksilver.