Temperamental means swinging between moods without warning. A temperamental artist, temperamental about food, she can be temperamental.
Applied to machines it means unreliable in an unpredictable way, and that is now at least as common: a temperamental boiler, the printer is temperamental. It is a gentler word than moody and slightly indulgent — calling somebody temperamental half excuses them. Note the neutral second sense meaning relating to temperament, which turns up in psychology: temperamental differences between siblings, where no criticism is meant at all.
1adjectivetemperamentalChanging mood suddenly and often.
“He is talented and thoroughly temperamental.”
2adjectivemachineOf a machine, working unreliably.
“The heating is temperamental in cold weather.”
3adjectiverelatingRelating to somebody's natural disposition.
“The temperamental differences showed from the first week.”
temperamental is a quality of unpredictability.
Also accepted in games: moody
Latin
temperāmentum
Middle French
tempérament
Middle English
temperament
English
temperament
English, today
temperamental
From temperament + -al. temperament Middle English temperament, borrowed from Middle French tempérament, from Latin temperāmentum.
Etymology from Wiktionary, CC BY-SA