mercurial
/məːˈkjʊə.ɹɪ.əl/adjective
Quick to change in mood or behaviour; lively and unpredictable.
Example sentences
- “Working for such a mercurial boss meant you never knew what each day would bring.”
- “The band's mercurial lead singer canceled concerts without warning.”
From the god Mercury, known for speed and cunning. Usually said of temperament, often of artists and leaders.