of, like, containing, or relating to mercury volatile; lively: a mercurial temperament - (sometimes capital)
of, like, or relating to the god or the planet Mercury
any salt of mercury for use as a medicine
WordReference Random House Learner's Dictionary of American English © 2025
mer•cu•ri•al /mərˈkyʊriəl/USA pronunciation adj.
WordReference Random House Unabridged Dictionary of American English © 2025- changeable;
varying;
erratic:a mercurial nature; a mercurial mood.
mer•cu•ri•al
(mər kyŏŏr′ē əl),USA pronunciation adj.
n.
mer•cu ′ri•al•ly, adv.
mer•cu ′ri•al•ness, mer•cu′ri•al′i•ty, n.
- changeable;
volatile;
fickle;
flighty;
erratic:a mercurial nature. - animated;
lively;
sprightly;
quick-witted. - Chemistrypertaining to, containing, or caused by the metal mercury.
- Mythology(cap.) of or pertaining to the god Mercury.
- Astronomy(cap.) of or pertaining to the planet Mercury.
n.
- Drugs[Pharm.]a preparation of mercury used as a drug.
- Latin mercuriālis of, pertaining to the god or planet Mercury. See mercury, -al1
- Middle English 1350–1400
mer•cu ′ri•al•ness, mer•cu′ri•al′i•ty, n.
- 1.See corresponding entry in Unabridged . inconstant, indecisive.
- 2.See corresponding entry in Unabridged . spirited.
- 1.See corresponding entry in Unabridged . constant, steady.
- 2.See corresponding entry in Unabridged . phlegmatic.
Collins Concise English Dictionary © HarperCollins Publishers::
'mercurial' also found in these entries (note: many are not synonyms or translations):
capricious
- even
- flighty
- inconstant
- merc
- mercurial barometer.
- mercurialism
- mercurialize
- mercury barometer
- salivate
- salivation
- variable
- volatile