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mercurial

mercurial

7 8.2
Changing mood or behaviour suddenly and without warning
  • adjective
  • /mɜrˈkjʊəriəl/
translation icon : caprichoso
  • He had a mercurial temper, shifting from laughter to anger in mere moments.
  • a mercurial personality

You know, Donald Trump has a lot of talent, but he's mercurial and capricious.

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Examples

  • In his early actions, the Mexican president has been mercurial and sometimes surprisingly unconventional.

    Academic text (2001)
  • U.S. leadership, such as House Speaker John Boehner, is very mercurial and has displayed hawkish tendencies recently.

    Blog text (9)
  • I never try to plan much because both life and Hollywood are mercurial.

    Academic text (2008)
  • In a time gone by, I would have been described as having a "mercurial personality."

    Blog text (26)
  • Robert displayed good business sense, but he also had a mercurial personality.

    Academic text (1990)
  • If you know he's so mercurial, how come you brought him?

    Fiction book (1996)
  • Sihanouk has a mercurial personality.

    Academic text (2002)
  • European powers have been just as mercurial in their alliance-building as any supposedly less principled powers.

    Blog text (16)
  • But Wesley's moods were mercurial, and he seemed to find what he had just said amusing.

    Fiction book (2001)
  • Pearson, who developed early misgivings over the conduct of the Vietnam War, learned firsthand of President Johnson's mercurial temperament.

    Academic text (1998)

Synonyms

erratic
vsmercurial
94 6.1

Not regular or predictable and likely to change suddenly

relates specifically to mood shifts rather than broader irregular actions
unstable
vsmercurial
91 4.4

A person whose mood or behavior changes suddenly

focuses on sudden mood changes rather than long term instability
volatile
vsmercurial
77 7.0

Likely to change suddenly and become more dangerous

denotes sudden mood shifts without implying escalation or danger
moody
vsmercurial
50 3.2

Often feels angry or sad quickly for no clear reason

is broader, covering sudden mood swings beyond unhappy or gloomy states
fickle
vsmercurial
39 6.2

Changing often in a way you cannot rely on

applies to rapid mood shifts rather than mainly loyalties or tastes
capricious
vsmercurial
19 7.9

Showing sudden changes in mood, like going from happy to angry

covers sudden mood shifts whether or not a cause is visible
temperamental
vsmercurial
12 6.5

Tends to change mood suddenly and act in an unexpected way

applies more generally to sudden mood shifts not only personal quirks
tempestuous
vsmercurial
7 8.4

Full of strong, stormy feelings, often with loud arguments

describes sudden mood change rather than sustained violent emotional turmoil
quicksilver
vsmercurial
  • Archaic
8.6

Likely to change mood or behavior quickly and without warning

is the common term for sudden unpredictable changes of mood
a bit switchy
vsmercurial
  • UK
9.2

Often changes mood or behavior quickly and without warning

is the stronger sense of sudden and fully unpredictable mood change

Antonyms

473 2.3

Not likely to change and stays steady over time

360 2.7

Stays the same over time

Compounds

9.9

An ointment with mercury used long ago to treat skin problems like lice and syphilis

How Changeable

volatile
77 7.0
mercurial
7 8.2
capricious
19 7.9
fickle
39 6.2
erratic
94 6.1
unstable
80 4.4

Surface Forms

mercurial positive
mercurialer comparative
mercurialest superlative

Morphology

mercurial = Mercury (semi-transparent) = mercury + ial

Built from 'Mercury' but the idiomatic extension to 'subject to sudden changes' is a metaphorical extension from attributes of the god/planet and may not be obvious to learners.

Etymology

Mercurial comes from Mercury, both the changeable god and the liquid metal, so a 'mercurial' person or mood is one that changes suddenly and is hard to predict.