temperamental
UK: /ˌtem.pər.əˈmen.təl/ | US: /ˌtem.pər.əˈmen.t̬əl/
adj. relating to or caused by temperament; moody or unpredictable
adj. (of a machine or system) prone to erratic performance
The word "temperamental" traces back to the Latin temperare ("to mix or regulate"), which evolved into temperamentum ("balance or moderation"). The root temper originally referred to balancing qualities (e.g., tempering metal). Over time, it shifted to describe innate behavioral tendencies (temperament), and the suffix -al extended it to mean "prone to mood swings" or "unpredictable." The modern sense reflects the idea of being governed by one's natural inclinations.
Her temperamental nature made teamwork challenging.
The old car was temperamental in cold weather.
Artists are often stereotyped as temperamental geniuses.
The software became temperamental after the update.
He apologized for his temperamental outburst earlier.