adjective
mercurial
mer-KYOOR-ee-ul/mɜːrˈkjʊriəl/
Subject to sudden changes of mood or behavior.
His mercurial mood shifts from laughter to irritation and back again.
Etymology
Being ‘of Mercury’ came to describe the quick, changeable temperament supposedly found in people born under that planet. This astrological character underlies the modern sense of unpredictable moods or behavior.
In context
the doctor obviously so much of the time is is Mercurial and one step ahead of everyone
More examples
- Our mercurial boss praises an idea, then angrily rejects it.
- Her mercurial temperament makes even casual conversations feel unpredictable.
- He's less mercurial these days, taking setbacks calmly.
Forms
mercurial
mercurially adverb — With sudden changes of mood or behavior.
Similar words
- volatile
- Emphasizes emotional instability, often with sudden anger or outbursts.
- capricious
- Emphasizes unpredictable whims or decisions rather than shifting moods.
- unpredictable
- Means difficult to anticipate, without necessarily suggesting sudden mood changes.